muricopsis ( muricopsis ) necocheana is a species of sea snail , a marine gastropod mollusk in the family muricidae , the murex snails or rock snails .

muricopsis necocheana

» species muricopsis ( muricopsis ) pauxilla ( a . adams , 1854 ) represented as muricopsis pauxilla ( a . adams , 1854 )
- - - - - - - - - - - - - - - species : muricopsis necocheana ( h . a . pilsbry , 1900 ) - id : 1901850090
species muricopsis spinulosa stalio in coen , 1933 accepted as muricopsis blainvillii var . spinulosa stalio in coen , 1933 accepted as muricopsis cristata ( brocchi , 1814 )
species muricopsis spinulosa ( costa o . g . , 1861 ) accepted as muricopsis aradasii ( poirier , 1883 ) accepted as murexsul aradasii ( monterosato in poirier , 1883 )
species muricopsis lyonsi petuch , 1986 accepted as murexsul oxytatus ( m . smith , 1938 )
muricopsis oxytata - hexagonal murex : synonym of murexsul oxytatus ( m . smith , 1938 )
muricopsis ednae ( m . smith , 1940 ) : synonym of murexsul interserratus ( sowerby , 1879 )
species muricopsis oxytatus ( m . smith , 1938 ) accepted as murexsul oxytatus ( m . smith , 1938 )
species muricopsis medicago ( r . b . watson , 1897 ) accepted as murexsul aradasii ( monterosato in poirier , 1883 )
species muricopsis nothokieneri ( e . h . vokes , 1978 ) accepted as murexsul nothokieneri e . h . vokes , 1978
species muricopsis noduliferus ( g . b . sowerby ii , 1841 ) accepted as attiliosa nodulifera ( g . b . sowerby ii , 1841 )
species muricopsis scotti b . a . marshall & k . w . burch , 2000 accepted as rolandiella scotti ( b . a . marshall & k . w . burch , 2000 )
species muricopsis personatus monterosato in settepassi , 1977 accepted as ocinebrina hispidula ( pallary , 1904 ) accepted as ocenebra hispidula ( pallary , 1904 ) ( unavailable following iczn art . 11 . 4 )
species muricopsis profunda b . a . marshall & k . w . burch , 2000 accepted as murexsul profundus ( b . a . marshall & k . w . burch , 2000 ) ( original combination )
subgenus muricopsis ( rolandiella ) b . a . marshall & k . w . burch , 2000 accepted as rolandiella b . a . marshall & k . w . burch , 2000 ( original rank as subgenus )
species muricopsis tenellus monterosato in settepassi , 1977 accepted as ocinebrina hybrida ( aradas & benoit , 1876 ) accepted as ocenebra hybrida ( aradas & benoit , 1876 ) ( unavailable following iczn art . 11 . 4 )
» species muricopsis ( murexsul ) profunda b . a . marshall & k . w . burch , 2000 accepted as murexsul profundus ( b . a . marshall & k . w . burch , 2000 ) ( original combination )
» species muricopsis ( rolandiella ) scotti b . a . marshall & k . w . burch , 2000 accepted as rolandiella scotti ( b . a . marshall & k . w . burch , 2000 ) ( original combination )
species muricopsis affinis settepassi , 1977 accepted as ocinebrina edwardsii ( payraudeau , 1826 ) accepted as ocenebra edwardsii ( payraudeau , 1826 ) ( not available , published in a work which does not consistently use binominal nomenclature ( iczn art . 11 . 4 ) )
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sistrum nicocheanum pilsbry , h . a . , 1900 : argentina ; brazil ( lapsus )
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references : castellanos ( 1970a ) sw ; leal ( 1991b ) ln ; houart ( 1991 ) l ; sunderland & sunderland ( 1993b ) dm ; e . h . vokes ( 1994 ) c
a new species of sistrum nautilus 14 3 - 4 . [ stated date : - - may 1900 . ]
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bucquoy e . , dautzenberg p . & dollfus g . ( 1882 - 1886 ) . les mollusques marins du roussillon . tome ier . gastropodes . paris , j . b . baillière & fils 570 p . , 66 pl . [ pp . 1 - 40 , pl . 1 - 5 , february 1882 ; pp . 41 - 84 , pl . 6 - 10 , august 1882 ; pp . 85 - 135 , pl . 11 - 15 , february 1883 ; pp . 136 - 196 , pl . 16 - 20 , august 1883 ; pp . 197 - 222 , pl . 21 - 25 , january 1884 ; pp . 223 - 258 , pl . 26 - 30 , february 1884 ; pp . 259 - 298 , pl . 31 - 35 , august 1884 ; pp . 299 - 342 , pl . 36 - 40 , september 1884 ; p . 343 - 386 , pl . 41 - 45 , february 1885 ; p . 387 - 418 , pl . 46 - 50 , august 1885 ; pp . 419 - 454 , pl . pl . 51 - 60 , january 1886 ; p . 455 - 486 , pl . 56 - 60 , april 1886 ; p . 487 - 570 , pl . 61 - 66 , october 1886 ] , available online at urltoken page ( s ) : 16 , 19 [ details ]
grammatical gender feminine under the provisions of iczn art . 30 . 1 . 2 .
a genus - group name that is or ends in a greek word transliterated into latin without other changes takes the gender given for that word in standard greek dictionaries ; examples . . . names ending in . . . - opsis ( opsis ) are feminine
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tulane university journal publishing is an open access , peer - reviewed journal publishing service which provides a web - based platform for scholarly and academic publishing to the tulane community .
tulane studies in geology and paleontology was devoted primarily to the geology and paleontology of the coasts and adjacent land areas of the gulf of mexico and the caribbean sea . each number
the journal was published between 1962 and 1997 . this is a collection of the entire run of the journal .
for all scientific names see vol . 10 , no . 4 ( taxonomic index to vol . 1 - 10 ) ; vol . 20 , no . 4 ( taxonomic index to vol . 11 to 20 ) ; vol . 30 , no . 4 ( taxonomic index to vol . 21 to 30 ) .
the past half century has seen dramatic changes in the world of scientific publishing ; changes that will continue in the next few decades . the newest generations of ( geo ) scientists have come of age in an environment where the research literature is almost entirely accessed online and visits to physical library collections are becoming increasingly rare . on one hand , these developments have led to the proliferation of new journals , most of which only exist online , and many of the latest additions are open - access journals . on the other hand , several older publication venues have come to a close .
it is now 20 years ago that the last issue of tulane studies in geology and paleontology ( initially known as tulane studies in geology ) appeared . coincidental or not , 1997 was right around the time that scientific publishing rapidly migrated to the internet . initiated in 1962 , tsgp has published more than 5000 pages of peer - reviewed research , in many cases by faculty members and graduate students in tulane’s department of geology . series like tsgp proliferated for many years , in part based on the extensive exchange schemes that existed between academic libraries . editing was carefully done in house , constituting a major time commitment for the faculty members who served as editors . even though the series was discontinued a while ago , the research published in tsgp has had a lasting impact . it continues to be cited on a regular basis and typically accrues 20 to 30 citations annually according to the web of science .
the tulane undergraduate research journal is a peer - reviewed research journal publishing articles from multiple academic fields . our goal is to unite the best undergraduate research from the tulane community and represent all academic fields producing a spectrum of high - quality and diverse work .
an online undergraduate journal featuring case studies authored by the newcomb scholars , an elite cohort of undergraduate women at tulane university .
the journal of community health promotion and research , sponsored by the tulane prevention research center ( prc ) , was planned to share information about public health work and disease - prevention programs focusing on the physical and social environment in the new orleans area .
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the tulane journal of international affairs is a newly formed undergraduate research journal at tulane university . publishing once a year , the journal promotes outstanding undergraduate work relating to its three sections : international security , international political economy , and human rights .
second line is a peer - edited journal at tulane university committed to the publication of original and intellectual undergraduate scholarship that engages in the various aspects of literary conversation .
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nemertea - taxonomy . . . comprises 100 marine species . . . comprises about 400 species . . . includes seven species , of which six live as commensals in the mantle of large clams and one in that of a freshwater snail . . .
nemertea . . . all species have a proboscis which lies in the rhynchocoel when inactive but everts ( turns inside - out ) to emerge just above the mouth and capture the animal ' s prey with venom . . . a few species with stubby bodies filter feed and have suckers at the front and back ends , with which they attach to a host . . . most nemerteans have various chemoreceptors , and on their heads some species have a number of pigment - cup ocelli , which can detect light but not form an image . . .
organic farming - externalities - biodiversity . . . nearly all non - crop , naturally occurring species observed in comparative farm land practice studies show a preference for organic farming both by abundance and diversity . . . an average of 30 % more species inhabit organic farms . . . many weed species attract beneficial insects that improve soil qualities and forage on weed pests . . .
orthoptera - life cycle . . . orthopteroid species have a paurometabolous life cycle or incomplete metamorphosis . . . the use of sound is generally crucial in courtship , and most species have distinct songs . . . the number of moults varies between species growth is also very variable and may take a few weeks to some months depending on food availability and weather conditions . . .
nemertea - description - nervous system and senses . . . most nemertean species have just one pair of nerve cords , many species have additional paired cords , and some species also have a dorsal cord . . . in some species the cords lie within the skin , but in most they are deeper , inside the muscle layers . . . some species have paired cerebral organs , sacs whose only openings are to the outside . . .
and kind of body as he pleaseth ? but i dare not say , that this is the way by which god almighty worketh , because it is past my apprehension : yet it serves very well to demonstrate , that the omnipotence of god implieth no contradiction .
the french manner of hunting is gentlemanlike ; ours is only for bumpkins and bodies . the poor beasts here are pursued and run down by much greater beasts than themselves ; and the true british fox - hunter is most undoubtedly a
appropriated and peculiar to this country , which no other part of the globe produces .
the genus ; through all genera the steadfast type ; through all the kingdoms of organized life the eternal unity . nature is a mutable cloud which is always and never the same .
1 laboratório de bioecologia e sistemática de crustáceos ( lbsc ) , departamento de biologia , faculdade de filosofia , ciências e letras de ribeirão preto ( ffclrp ) , universidade de são paulo ( usp ) . av . bandeirantes , 3900 . 14040 - 901 ribeirão preto , são paulo , brazil .
2 núcleo integrado de biotecnologia , universidade de mogi das cruzes . av . dr . cândido xavier de almeida e sousa , 200 . 08780 - 911 mogi das cruzes , são paulo , brazil .
located in ubatuba city , anchieta island ( 23 ( 33 ' s 45 ( 05 ' w ) is the second largest island of the north coast of são paulo state , with a total area of about 10 km 2 . this island has been affected by anthropogenic activities such as tourism and fishery exploitation until 1977 , when it was declared an ecological reserve of são paulo state ( see mantelatto and garcia , 2002 for details ) .
the mean size of individuals of both sexes was compared by the mann - whitney test ( zar , 1996 ) . the level of significance was 0 . 05 .
the relations between hermit crabs size and shell variables were determined by regression analysis and by correlation coefficients . the chi - square test ( ( 2 ) was used to compare occupancy percentage of shell species between males , ovigerous females and non - ovigerous females .
after the knowledge of the population profile ( mantelatto and garcia , 2002 ; mantelatto et al . , 2007 ) and of the pattern of shell utilization by this population in the field , two types of laboratory experiments were performed : shell species and size preferences , which were conducted for the most occupied shell types in the field . for this , samples were additionally carried out during 2002 in the same area , following the above described method of collection .
three replicates were conducted for each type of experiment , which occurred in a glass aquarium ( 30x30x40 cm ) with flowing and oxygen - saturated seawater , where the animals chosen independently of sex or size ( n = 15 ) were placed naked with a large number of shells ( n = 150 ) , during 72 hours ( time previously established ) . after that , the hermit crabs were removed from the preferred shell , and both were measured as described above for shell occupation . each animal was used only once in order to avoid any acquired behavior .
the shell species experiments were conducted in pair - wise fashion , i . e . , the hermit crabs were placed in the aquarium with empty shells of two different species and similar size ( 75 of each species ) than those found in the field . shell size preference was tested separately for most occupied shell species using shells of the same species but of varied sizes . all experiments were performed according to method described by garcia and mantelatto ( 2001 ) .
shell species preference was estimated based on the frequency of which species was chosen by the individuals . the chi - square test ( ( 2 ) was used to compare occupancy percentage of shell species . morphometric relationships were established by regression analysis and spearman correlation coefficients ( r s ) ( p < 0 . 05 ) . shell fitness of hermit crabs collected in the field was assessed using a shell adequacy index ( sai ) ( vance , 1972a ) . this index is defined as : sai = suitable crab size / actual crab size , where sai = 1 indicates that , in field , the animal occupies a shell of adequate size while sai ( 1 indicates a crab in a shell larger ( sai > 1 ) or smaller ( sai < 1 ) than adequate size .
in total , 992 individuals were collected , represented by 432 ( 43 . 55 % ) males , 263 ( 26 . 51 % ) non - ovigerous females , and 297 ( 29 . 94 % ) ovigerous females . the mean size of population was 1 . 88 ( 0 . 39 mm csl , being females ( 1 . 85 ± 0 . 35 mm csl ) significantly smaller than males ( 1 . 92 ± 0 . 31 mm ) .
pagurus criniticornis was found occupying 16 species of gastropod shells in the natural habitat ( tab . 1 ) . cerithium atratum ( born , 1778 ) was the most occupied shell ( 89 . 31 % ) , followed by morula nodulosa ( adams , 1845 ) ( 4 . 73 % ) . from the total ( 992 ) of shells collected , 2 . 42 % were much damaged , and thus non identifiable .
list of gastropod shells occupied by pagurus criniticornis at anchieta island , são paulo , brazil .
shell species occupation as a function of hermit crab size is illustrated ( fig . 1 ) . the diversity of shells utilized decreased with the increase of individuals ' size . cerithium atratum was the most occupied shell in all size classes , except in the first class , where this corresponded to 12 . 5 % of occupied shells . there was no difference between species of shell occupied by males , ovigerous females and non - ovigerous females .
pagurus criniticornis . gastropod shell species occupation as a function of hermit crab size . ( csl = cephalothoracic shield length ) .
the relationship between the shells and the hermit crabs was tested only to c . atratum and m . nodulosa , due to a low percentage of occupation for the other species of gastropod shells . the equations that best demonstrated this relationship were those that involved shell wet weight ( sww ) and shell internal volume ( siv ) ( tab . 2 ) , mainly to the most occupied shell species , c . atratum .
pagurus criniticornis . regression equations for measures between hermit crab ( csl = cephalothoracic shield length and ww = hermit crab wet weight ) and the two most occupied species of shells ( saw = shell aperture width ; sal = shell aperture length ; sww = shell wet weight ; siv = shell internal volume ) . [ n = number of individuals ; r s = spearman correlation coefficient ] .
the experiments were conducted only for most the occupied species of shell , i . e . , c . atratum and m . nodulosa .
forty - three animals were utilized ( 21 males , 14 non - ovigerous females and 8 ovigerous females ) . males ( χ 2 = 17 . 19 ) and non - ovigerous females ( χ 2 = 4 . 57 ) of pagurus criniticornis , but not ovigerous females ( χ 2 = 2 . 00 ) , showed a significant ( p < 0 . 05 ) preference by c . atratum ( tab . 3 ) .
pagurus criniticornis . laboratory shell species preference observed among the two most occupied in the field .
one hundred one animals were utilized ( 48 males , 32 non - ovigerous females and 21 ovigerous females ) . all relations between dimensions of hermit crabs and selected shells were significant ( p < 0 . 05 ) , but p . criniticornis showed a preference strongly associated with siv and sww . the higher correlation coefficients demonstrated that c . atratum shells are most adequate to the various hermit crab sizes ( tab . 4 ) . the pattern of shell choice of males , non - ovigerous females and ovigerous females was not different for both species of shells ( tabs . 5 , 6 ) .
pagurus criniticornis . regression analysis for each chosen shell size ( csl = cephalothoracic shield length ; ww = hermit crab wet weight ; saw = shell aperture width ; sww = shell wet weight ; siv = shell internal volume ; n = number of individuals ; r s = spearman correlation coefficient ) .
pagurus criniticornis . regression equations for measures between hermit crab and the shells of cerithium atratum chosen under laboratory conditions , according to sexes . ( csl = cephalothoracic shield length ; ww = hermit crab wet weight ; saw = shell aperture width ; sww = shell wet weight ; siv = shell internal volume ; n = number of individuals ; r s = spearman correlation coefficient ) .
pagurus criniticornis . regression equations for measures between hermit crab and the shells of morula nodulosa chosen under laboratory conditions , according to sexes . ( csl = cephalothoracic shield length ; ww = hermit crab wet weight ; saw = shell aperture width ; sww = shell wet weight ; siv = shell internal volume ; n = number of individuals ; rs = spearman correlation coefficient ) .
the mean sai value found to p . criniticornis population was 1 . 13 ( 0 . 25 . shells occupied by hermit crabs in the field were larger than adequate size ( sai > 1 ) in the most size classes ; however , larger individuals showed a trend to occupy shells of adequate size ( sai = 1 ) .
there were no differences in this pattern observed between males , non - ovigerous females and ovigerous females ( fig . 2 ) . for the two most occupied shell species tested the pattern of adequacy was similar , i . e . , sai > 1 in the first size classes and this adequacy increased as the hermit crabs reached higher size classes ( fig . 3 ) .
pagurus criniticornis . variation of the mean shell adequacy index ( sai ) values for total of population , males , non - ovigerous females and ovigerous females . ( data are expressed as mean ± sd )
pagurus criniticornis . variation of the shell adequacy index ( sai ) values for each most occupied shell species in relation to the size classes . ( data are expressed as mean ± sd )
the pattern of shell utilization by hermit crabs is a result of a complex interaction among availability of shells ( reese , 1969 ; bertness , 1980 ; mantelatto and garcia , 2000 ; mantelatto and dominciano , 2002 ; mantelatto and meireles , 2004 ) and selection of this resource , considering that hermit crabs can discriminate between different species and size of shells ( reese , 1962 ; 1963 ; markham , 1968 ; young , 1979 ; hazlett , 1996 ; mantelatto and meireles , 2004 ) .
shell occupation pattern was more diverse in the initial size classes of p . criniticornis . according to bollay ( 1964 ) , individuals of smallest size tend to occur in most variety of small shells , since these are not heavily dependent on species of shells to survive and reproduce .
patterns of shell utilization vary between hermit crab populations and are influenced by the type and size of shells available in the survey , the locality and hermit crabs ' shell preference ( mantelatto and garcia , 2002 ) . lively ( 1988 ) and osorno et al . ( 1998 ) affirmed that hermit crabs prefer shells which the architecture maximizes their internal space . the present study corroborated this hypothesis , considering the good correlation values found between hermit crabs and c . atratum shells , mainly those related with weight and internal volume .
the shell occupation pattern of p . criniticornis showed similarity with availability of shells in the area ; however , the rate of occupation of c . atratum and m . nodulosa by p . criniticornis was not proportional to the rate of availability found by meireles et al . ( 2003 ) , suggesting the preference for c . atratum as commented by meireles et al . ( 2008 ) . the experimental results confirmed the strong preference of individuals of this population for c . atratum shells , independently of sexes . this allows us to infer that this population ' s dynamics is directly related with c . atratum occupation .
the mean sai value found for the population of p . criniticornis was 1 . 13 , which means that , in general , these animals utilize shells larger than the suitable size . however , value of shell adequacy index decreased with increase of crab size showing that the larger individuals were occupying relatively adequate shells . meireles and mantelatto ( 2005 ) observed similar pattern for the coexistent population of pagurus brevidactylus from anchieta island .
the occupancy of larger shells than the adequate size by small individuals can be caused by an insufficient availability of small shells ( gherardi et al . , 1994 ) . according to mantelatto and meireles ( 2004 ) , small shells represent a limited resource to the hermit crabs from anchieta island . moreover , c . atratum was occupied by five of nine hermit crabs species that live in this area ( mantelatto and garcia , 2002 ) . in this case , the acquisition of shells larger than the adequate size is less strenuous than a continuous search for ideal sized shells .
in this way , the occurrence of individuals occupying larger shells than adequate ones is advantageous , since the interaction between specimens of the same population is more frequent than the probability of finding new and empty shells ( spight , 1977 ; 1985 ) . these interactions allow changes that lead to better adequacy of individuals to their shells ( vance , 1972b ) and consequently increase the potential of population growth . thus , we are convinced that the pattern of adequacy observed in the studied population would be a satisfactory way to minimize the interspecific competition that it is exposed to .
the results obtained here indicate that the pattern of occupation found to p . criniticornis population is probably conducted by the availability of shells on the locality and by hermit crabs ' choice of this resource , considering the relatively abundance of c . atratum on studied area and , additionally , the good adequacy of shell and hermit crab morphological characteristics , which is evidenced by high correlation coefficients , being , however , the second factor more influent under the determination of this pattern .
in recent studies , it was corroborated that in p . criniticornis population , there is a range of factors that influences shell exchange , and that some of them could represent trade - offs between immediate and long - term survival ( buranelli et al . , 2015 ) . in other words , these authors postulated that hermit crabs face different trade - offs related to the behavior of choice , selection , and exchange of shells , indicating that different factors may affect behavior , depending on many aspects as environmental features , sex , individual size , shell size , and shell quality .
bertness , m . d . 1980 . shell preference and utilization patterns in littoral hermit crabs of the bay of panama . journal of experimental marine biology and ecology , 48 ( 1 ) : 1 - 16 . [ links ]
bertness , m . d . 1981a . pattern and plasticity in tropical hermit crab growth and reproduction . american naturalist , 117 ( 5 ) : 754 - 773 . [ links ]
bertness , m . d . 1981b . the influence of shell - type on hermit crab growth rate and clutch size . crustaceana , 40 ( 2 ) : 197 - 205 . [ links ]
biagi , r . ; meireles , a . l . and mantelatto , f . l . 2006 . bio - ecological aspects of the hermit crab paguristes calliopsis ( crustacea , diogenidae ) from anchieta island , brazil . anais da academia brasileira de ciências , 78 ( 3 ) : 451 - 462 . [ links ]
bollay , m . 1964 . distribution and utilization of gastropod shells by the hermit crabs p . samuelis , p . granosimanus and p . hirsutiusculus at pacific groove , california . the veliger , 6 ( suppl . ) : 71 - 76 . [ links ]
buranelli , r . c . ; marcondes , a . t . p . ; carbonaro , f . a . ; miyazaki , m . j . ; pardo , l . m . and mantelatto , f . l . 2015 . behavioral trade - off on shell exchange and exploration of the white spotwrist hermit crab pagurus criniticornis ( crustacea , anomura , paguridae ) . crustacean research , 44 : 55 - 66 . [ links ]
dominciano , l . c . c . , sant ' anna , b . s . and turra , a . 2009 . are the preference and selection patterns of hermit crabs for gastropod shells species or site - specific ? journal of experimental marine biology and ecology , 378 ( 1 ) : 15 - 21 . [ links ]
garcia , r . b . and mantelatto , f . l . 2001 . shell selection by the tropical hermit crab calcinus tibicen ( herbst , 1791 ) ( anomura , diogenidae ) from southern brazil . journal of experimental marine biology and ecology , 265 : 1 - 14 . [ links ]
gherardi , f . ; zatteri , f . and vannini , m 1994 . hermit crabs in a mangrove swamp : the structure of clibanarius laevimanus clusters . marine biology , 121 : 41 - 52 . [ links ]
hazlett , b . a . 1996 . recent experience and the shell size preference of hermit crabs . marine and freshwater behavior and physiology , 28 ( 3 ) : 177 - 182 . [ links ]
lively , c . m . 1988 . a graphical model for shell - species selection by hermit crabs . ecology , 69 ( 4 ) : 1233 - 1238 . [ links ]
mantelatto , f . l . and dominciano , l . c . 2002 . pattern of shell utilization by the hermit crab paguristes tortugae ( diogenidae ) from anchieta island , southern brazil . scientia marina , 66 ( 3 ) : 265 - 272 . [ links ]
mantelatto , f . l . ; faria , f . c . ; iossi , c . l . and biagi , r . 2007 . population and reproductive features of the western atlantic hermit crab pagurus criniticornis ( anomura , paguridae ) from anchieta island , southeastern brazil . iheringia , série zoologia , 97 ( 3 ) : 1 - 7 . [ links ]
mantelatto , f . l . and garcia , r . b . 2000 . shell utilization pattern of the hermit crab calcinus tibicen ( diogenidae ) from southern brazil . journal of crustacean biology , 20 ( 3 ) : 460 - 467 . [ links ]
mantelatto , f . l . and garcia , r . b . 2002 . hermit crab fauna from the infralittoral area of anchieta island ( ubatuba , brazil ) . p . 137 - 145 . in : e . e . briones and f . alvarez ( eds ) , modern approaches to the studies of crustacean . new york , kluwer academic / plenum publishers . [ links ]
mantelatto , f . l . and meireles , a . l . 2004 . the importance of shell occupation and shell availability clustering in the hermit crab pagurus brevidactylus ( stimpson , 1859 ) ( paguridae ) population from the southern atlantic . bulletin of marine science , 75 ( 1 ) : 27 - 35 . [ links ]
markham , j . 1968 . note on the growth patterns and shell utilization of hermit crab pagurus bernhardus ( l . ) . ophelia , 5 : 189 - 205 . [ links ]
meireles , a . l . ; biagi , r . and mantelatto , f . l . 2003 . gastropod shell availability as a potential resource for the hermit crab infralittoral fauna of anchieta island ( sp ) , brazil . nauplius , 11 ( 2 ) : 99 - 105 . [ links ]
meireles , a . l . ; biagi , r . and mantelatto , f . l . 2008 . influence of prior experience on shell selection by the white spotwrist hermit crab pagurus criniticornis ( crustacea : paguridae ) . hydrobiologia , 605 : 259 - 263 . [ links ]
meireles , a . l . ; biagi , r . ; fransozo , a . and mantelatto , f . l . 2012 . os ermitões ( crustacea , anomura ) . p . 479 - 488 . in : a . c . z . amaral & s . a . h . nallin ( orgs ) , biodiversidade e ecossistemas bentônicos marinhos do litoral norte de são paulo - sudeste do brasil . campinas , sp , ib / unicamp . e - book - isbn : 978 - 85 - 85783 - 24 - 2 urltoken [ links ]
meireles , a . l . and mantelatto , f . l . 2005 . shell use by pagurus brevidactylus ( anomura : paguridae ) : a comparison between laboratory and field conditions . acta zoologica sinica , 51 ( 5 ) : 813 - 820 . [ links ]
melo , g . a . s . 1999 . manual de identificação dos crustacea decapoda do litoral brasileiro : anomura , thalassinidea , palinuridea , astacidea . são paulo , editora plêiade , 551p . [ links ]
ohmori , h . ; wada , s . ; goshima , s . and nakao , s . 1995 . effects of body size and shell availability on the shell utilization pattern of the hermit crab pagurus filholi ( anomura : paguridae ) . crustacean research , 24 : 85 - 92 . [ links ]
osorno , j . l . ; fernández - casillas , l . and rodríguez - juárez , c . 1998 . are hermit crabs looking for light and large shells ? : evidence from natural and field induced shell exchanges . journal of experimental marine biology and ecology , 222 ( 1 - 2 ) : 163 - 173 . [ links ]
reese , e . s . 1962 . shell selection behaviour of hermit crabs . animal behaviour , 10 ( 3 - 4 ) : 347 - 360 . [ links ]
reese , e . s . 1963 . the behavioral mechanisms underlying shell selection by hermit crabs . behaviour , 21 : 78 - 126 . [ links ]
reese , e . s . 1969 . behavioral adaptations of intertidal hermit crabs . american zoologist , 9 ( 2 ) : 343 - 355 . [ links ]
rios , e . c . 1994 . seashells of brazil . rio grande , fundação cidade do rio grande , instituto acqua , museu oceanográfico de rio grande , universidade de rio grande . 2a ed . , 368p + 113pl . [ links ]
spight , t . m . 1977 . availability and use of shells by intertidal hermit crabs . the biological bulletin , 152 ( 1 ) : 120 - 133 . [ links ]
spight , t . m . 1985 . why small hermit crabs have large shells . research on population ecology , 27 ( 1 ) : 39 - 54 . [ links ]
turra , a . and denadai , m . r . 2004 . interference and exploitation components in interespecific competition between sympatric intertidal hermit crabs . journal of experimental marine biology and ecology , 310 ( 2 ) : 183 - 193 . [ links ]
vance , r . r . 1972a . the role of shell adequacy in behavioral interactions involving hermit crabs . ecology , 53 ( 6 ) , 1075 - 1083 . [ links ]
vance , r . r . 1972b . competition and mechanism of coexistence of three sympatric species of intertidal hermit crabs . ecology , 53 ( 6 ) : 1062 - 1074 . [ links ]
young , a . m . 1979 . osmoregulation in three hermit crab species , clibanarius vittatus ( bosc ) , pagurus longicarpus say and p . pollicaris say ( crustacea : decapoda ; anomura ) . comparative biochemistry and physiology , 63a ( 3 ) : 377 - 382 . [ links ]
zar , j . h . 1996 . biostatiscal analysis . new jersey , prentice - hall , 907p . [ links ]
1 this article is part of the special series offered by the brazilian crustacean society in honor to nilton josé hebling in recognition of his dedication and contributions to the development of carcinology in brazil .
instituto de biociências , unesp , campus botucatu rua professor doutor antônio celso wagner zanin , 250 botucatu , sp , 18618 - 689 editor . nauplius @ urltoken


achyra nigrirenalis is a moth in the crambidae family .

it was described by hampson in 1913 .

it is found in australia , where it has been recorded from western australia , the northern territory , queensland and south australia .

the wingspan is about 25 millimetres ( 0.98 in ) .

the hindwings are uniform pale brown .

achyra nigrirenalis

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valter jacinto marked
borboleta nocturna / / moth ( achyra nudalis )
as trusted on the
achyra nudalis
page .
no one has contributed data records for achyra serrulata yet . learn how to contribute .
jennifer hammock split the classifications by bolds resource for species - level taxa from achyra to their own page .
the adult moth of this species has light and dark brown patterned forewings , including one or two vague darker broad incomplete bands each one . the hindwings are plain pale brown . the moth has a wingspan of about 2 . 5 cms .
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hampson , g . f . 1913 ,
descriptions of new species of pyralidae of the subfamily pyraustinae ( continued )
, annals and magazine of natural history , ser . 8 , vol . 12 , pp . 1 - 38 , 299 - 319
urn : lsid : biodiversity . org . au : afd . taxon : 112a2bdb - 1317 - 4eef - 89eb - 14c860272237
urn : lsid : biodiversity . org . au : afd . taxon : 164ceae0 - c7ad - 4131 - 9ae6 - 769aa88a833d
urn : lsid : biodiversity . org . au : afd . taxon : 9b0b7346 - 01bd - 452d - 996e - 34f4a3b27c94
urn : lsid : biodiversity . org . au : afd . taxon : e3453510 - ffca - 42a8 - 9f0b - e00676fead83
urn : lsid : biodiversity . org . au : afd . name : 354164
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mm . the forewings have a light and dark brown pattern . the hindwings are uniform pale brown .
this article is issued from wikipedia - version of the 7 / 1 / 2015 . the text is available under the creative commons attribution / share alike but additional terms may apply for the media files .
this sighting hasn ' t been described yet ! be the first to describe this sighting .
arizona , texas , mexico - brazil - argentina , west indies . see [ maps ]
larva on gossypium , portulaca [ mna13 . 2 ] ( a ) , 47
from ( maine - s . quebec - ontario ) - to ( florida - mexico ) , iowa , colorado , california , west indies . see [ maps ]
brazil ( rio grande do sul , mato grosso , minas gerais , são paulo , rio de janeiro , castro parana ) , uruguay , paraguay , argentina , chile , bolivia , ecuador . see [ maps ]
loxostege similalis ; capps , 1967 , proc . u . s . nat . mus . 120 ( 3561 ) : 51 , f . 50 , 95 , 157 - 158
scopula occidentalis packard , 1873 ; ann . lyc . nat . hist . n . y . 10 : 260 ; tl : california
loxostege brasiliensis capps , 1967 ; proc . u . s . nat . mus . 120 ( 3561 ) : 55 , f . 55 , 99 , 166 - 167 ; tl : campinas , são paulo , brazil
loxostege piuralis capps , 1967 ; proc . u . s . nat . mus . 120 ( 3561 ) : 55 , f . 57 , 100 , 168 - 169 ; tl : piura , peru
tritaea protealis warren , 1892 ; ann . mag . nat . hist . ( 6 ) 9 ( 50 ) : 178 ; tl : san lorenzo is . , callao , peru
pyrausta eneanalis schaus , 1923 ; zoologica 5 ( 2 ) : 45 ; tl : conway bay , indefatigable island , galapagos arch .
this information is not automatically synchronized with globiz and can sometimes be lagging behind .
[ maps ] warning ! the maps are automatically generated from the textual information , and the process does not always produce acceptable result ; see about maps for more info .
histoire naturelle des insectes . species général des lépidoptéres . tome huitiéme . deltoides et pyralites
a revision of the moths of the subfamily pyraustinae and family pyralidae . part 2
exploration scientifique de l ' algerie pendant les annees 1840 , 1841 , 1842 . histoire naturelle des animaux articules ( 3 ) insectes
( a ) : 1 - 78 , pl . 1 - 4 , a - h , ( b ) : 79 - 150 , pl . 5 - 9 , j - u
list of the specimens of lepidopterous insects in the collection of the british museum . supplement
warren , 1892 descriptions of new genera and species of pyralidae contained in the british - museum collection ann . mag . nat . hist . ( 6 ) 9 ( 50 ) : 172 - 179 , ( 52 ) : 294 - 302 , ( 53 ) : 389 - 397 , ( 54 ) : 429 - 442
if you have corrections , comments or information to add into these pages , just send mail to markku savela keep in mind that the taxonomic information is copied from various sources , and may include many inaccuracies . expert help is welcome .
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curators : konstantin efetov , vasiliy feoktistov , svyatoslav knyazev , evgeny komarov , stan korb , alexander zhakov .
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the tritheledontidae or tritheledontids , also known as ictidosaurs , were small to medium-sized ( about 10 or 20 cm long ) cynodonts .

they were extremely mammal-like , highly specialized cynodonts , although they still retained a very few reptilian anatomical traits .

tritheledontids were mainly carnivorous or insectivorous , though some species may have developed omnivorous traits .

their skeletons show that they had a close relationship to mammals .

tritheledontids or their closest relatives may have given rise to primitive mammals .

the tritheledontids were one of the longest lived non-mammalian therapsid lineages , living from late triassic to the jurassic period .

tritheledontids became extinct in the jurassic period , possibly due to competition with prehistoric mammals such as the triconodonts .

they are known from finds in south america and south africa , indicating that they may have lived only on the supercontinent of gondwana .

the family tritheledontidae was named by south african paleontologist robert broom in 1912 .

the family is often misspelled " trithelodontidae " .

it is possible that tritheledontidae had vibrissae , according to the pbs documentary , your inner fish .

a common ancestor of all therian mammals did so .

it is possible that the development of the whisker sensory system played an important role in mammalian development , more generally .

tritheledontidae

the dentitions of the tritheledontidae ( therapsida : cynodontia ) . - pubmed - ncbi
zu den tritheledontidae , welche basal der chalimininae und pachygenelinae stehen . unter den vorher unbekannten merkmale von
gow , c . e . 1980 . the dentitions of the tritheledontidae ( therapsida : cynodontia ) .
links : tritheledont tooth ; jurassic cynodonts ; tritylodontidae and tritheledontidae , an internet directory ; universidad caece - cursos y seminarios .
( eucynodontia , tritheledontidae ) from the caturita formation , upper triassic of southern brazil : anatomical study and phylogenetic implications . in
links : parrs . htm ; tritheledont tooth ; jurassic cynodonts ; tritylodontidae and tritheledontidae , an internet directory ; universidad caece - cursos y seminarios .
links : lecture 12 - early jurassic ; therapsd . htm ; ciencia hoy 32 - artículo ; traces ; jawtransition ; jurassic cynodonts ; tritylodontidae and tritheledontidae , an internet directory . wikipedia
( cynodontia , tritheledontidae ) do triássico superior do rio grande do sul , brasil : análise osteológica e implicações filogenéticas . unpublished ph . d . thesis , universidade federal do rio grande do sul , 347 .
has alternatively been referred to dromatheriidae . another possibility is at least in part affinities with tritheledontidae . this is a matter which will require further finds and study . the south american critters were mousey or ratty - sized , whilst meurthodon was even smaller .
- like members of tritheledontidae , ( also known as trithelodontidae ) . these were small insectivores of up to 20cm in length , and their lifestyle was presumably extremely similar to that of the first mammals . this may well explain their disappearance . remains are known from the upper
. this is incorrect , as already demonstrated by members of tritheledontidae , ( those insectivores mentioned above ) . tritylodonts were their plant - eating counterparts . they were generally larger , ( up to about 50cm in length ) and survived for longer ; until at least the lower
although previously separated from other theriodonts as a distinct infraorder , the ictidosauria , study of the type and only specimen of the genus the trithelodon has determined its close affinities with the typical ictidosaurs pachygenelus and
diarthrognathus
. for this reason , hopson & kitching ( 1972 ) suggested using the family name tritheledontidae broom 1912 for all of the forms called
ictidosaurs
, and included all these groups under the cynodontia .
ictidosaurian genera are allocated to two families , tritheledontidae and therioherpetidae . this paper provides a diagnosis for ictidosauria . the previously named family brasilodontidae is shown to be a junior synonym of a family , therioherpetidae . it is concluded that ictidosauria originated from late permian procynosuchid non - mammalian cynodonts rather than from middle triassic probainognathid non - mammalian cynodonts . the structure of the skull and jaws of a derived traversodontid ischignathus sudamericanus from the early late triassic of argentina supports an earlier view that tritylodontids are more closely related to traversodontid than probainognathid non - mammalian cynodonts . tritylodontids should not be included in ictidosauria , nor should they considered to be a sister group to mammaliaforms .
three previously described monospecific genera of ictidosaurians ( tritheledontidae ) are recognized on the basis of their postcanine dentitions . the least specialized is pachygenelus monus , watson ( 1913 ) , the complete dentition of which is described for the first time : five specimens are described and referred to this species . the postcanine teeth of diarthrognathus broomi , crompton ( 1958 ) are described for the first time ; they are derivable from those of pachygenelus though considerably more specialized . tritheledon riconoi , broom ( 1912 ) , from which the family derives its name , consists of a single specimen containing upper postcanines only ; these are not closely comparable with the uppers of the other two genera but bear a strong resemblance to the lower postcanines of diarthrognathus . the family is closely implicated in the origin of mammals and the possibility of polyphyly in the origin of mammals is raised .
three previously described monospecific genera of ictidosaurians ( tritheledontidae ) are recognized on the basis of their postcanine dentitions . the least specialized is pachygenelus monus , watson ( 1913 ) , the complete dentition of which is described for the first time : five specimens are described and referred to this species . the postcanine teeth of diarthrognathus broomi , crompton ( 1958 ) are described for the first time ; they are derivable from those of pachygenelus though considerably more specialized . tritheledon riconoi , broom ( 1912 ) , from which the family derives its name , consists of a single specimen containing upper post - canines only ; these are not closely comparable with the uppers of the other two genera but bear a strong resemblance to the lower postcanines of diarthrognathus . the family is closely implicated in the origin of mammals and the possibility of polyphyly in the origin of mammals is raised .
in this contribution , new specimens of the tritheledontid eucynodont irajatherium hernandezi , from the late triassic ( caturrita formation ) of southern brazil , are analyzed . the new material provides significant information about incisor count , canine size and shape , basicranial morphology , and other previously unknown aspects of skull and dentition . a cladistic analysis with inclusion of the new data supports the assignment of irajatherium to tritheledontidae , basal to chalimininae and pachygenelinae . previously unknown characters of irajatherium revealed by the new material include : the presence of three lower incisors ; the first lower incisor is enlarged ; the presence of large upper and lower canines with deep paracanine fossa on the maxilla ; almost complete upper and lower postcanine tooth row with a pattern similar to that of other tritheledontids ( e . g . pachygenelus and chaliminia ) ; there is a conspicuous crest on the inner surface of the maxilla for the attachment of the inferred maxillary turbinates ; partially confluent jugular foramen and fenestra rotunda within the jugular fossa , separated by a finger - like projection of the posterolateral wall of the opisthotic ; and hypoglossal foramina located outside the jugular fossa . irajatherium is a key taxon for understanding the early evolution of ictidosaurs , a group of cynodonts closely related to mammaliaforms , during the cynodont–mammal transition from the late triassic to early jurassic .
have you ever wondered why our bodies look the way they do ? paleobiologist neil shubin sets out in this three - part series to find the answers in a surprising place : the ancient animal ancestors that shaped our anatomy .
in the first episode ,
your inner fish ,
he journeys back to a time , some 375 million years ago , when the first fish crawled up onto land . shubin ' s quest for the fossil record of this primeval predecessor takes viewers from highway cuts in rural pennsylvania to the remote arctic . after years of searching , he and his colleagues finally found a fossilized fish , known as tiktaalik , that had enough strength in its front fins to do pushups and heave itself out of the water . remarkably , we can trace the ancestry of our own hands and arms all the way back to these fins . viewers also meet the scientists who discovered the dna recipe for constructing the human hand — an essential set of instructions passed down from fish like tiktaalik and shared today with a surprising number of other animals , from chickens to chimpanzees . along the way , shubin makes it clear that we can also thank our fishy past for many of our body ' s quirks , such as hernias . we are , every one of us , just a jury - rigged fish .
in the second episode ,
your inner reptile ,
shubin exposes our reptilian roots . he searches for our ancient ancestors at fossil sites in the karoo desert of south africa and on the tidal flats of nova scotia . he also reveals modern - day links to the past through visits to a fertility clinic in chicago and a biology lab in london . along the way , he explains how major transitions in the history of life paved the way for our ancestors ' evolution into mammals . shubin identifies some amazing connections : the amniotic sac was an innovation to keep our reptile ancestors ' eggs from drying out ; our complex teeth can be traced to ferocious beasts that lived millions of years before dinosaurs ; and our hair is linked to the whiskers of reptile - like mammals that lived much of their lives in the dark . our reptilian ancestors — from fearsome predators to creatures as small as a paper clip — are responsible for more than a few features of modern humans .
in the final episode of the series ,
your inner monkey ,
shubin delves into our primate past . he travels from the badlands of ethiopia , where the famous hominid skeletons
lucy
and
ardi
were found , to a forest canopy in florida , home to modern primates . en route , he explains how many aspects of our form and function evolved . we learn that a genetic mutation in our primate ancestors conferred humans ' ability to see in color — but it was an advantage that led to a decline in our sense of smell . the shape of our hands came from tree - dwelling ancestors for whom long fingers made it easier to reach fruit at the tips of fine branches . shubin concludes by tracing the evolution of the human brain — from a tiny swelling on the nerve cord of a wormlike creature , to the three - part architecture of a shark ' s brain and the complex brain of primates . as shubin observes ,
inside every organ , gene and cell in our body lie deep connections with the rest of life on our planet .
© copyright 2014 tangled bank studios . all rights reserved . pbs privacy policy | terms of use | contact us
tangled bank studios is a production company established and funded by the howard hughes medical institute .
pbs is a 501 ( c ) ( 3 ) not - for - profit organization .
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author ' s note : these pages were written some years ago . i am not planning to update them . for a more current coverage , see the palaeos website ( to which many links on these pages point to anyway . more info here
the trithelodontids , also and better known ( especuially in earlier literature ) as the ictidosaurs , were tiny latest triassic and early jurassic cynodonts that neatly bridge the gap between advanced theriodonts and the primitive mammals .
although previously separated from other theriodonts as a distinct infraorder , the ictidosauria , study of the type and only specimen of the genus the trithelodon has determined its close affinities with the typical ictidosaurs pachygenelus and
diarthrognathus
. for this reason , hopson and kitching suggested using the family name trithelodontidae broom 1912 for all of the forms called
ictidosaurs
, and included all these groups under the cynodontia .
the trithelodonts ( ictidosaurs ) are thus very advanced , probably insectivorous , cynodonts of small size in which some incisors and in some species the upper and probably postcanines have a transversely - oriented cutting edge , in others the uppers have an oblique and the lowers a longitudinal cutting edge . these are features connected , as in the tritylodonts , with the more efficient chewing of food . as in the chiniquodontidae the secondary palate is long ( so the animal could eat and breathe at the same time , a mammalian feature ) and the postorbital bar ( the bar of bone behind the eyes ) is absent , another feature found also in tritylodonts and primitive mammals .
but what makes these animals unique is the new mammalian joint between the squamosal and dentary had come into functional being . thus , the ictidosaur pachygenelius ( formerly known as diarthrognathus ) possesses both the reptilian quadrate - articular jaw joint and a newly developed mammalian squamosal - dentary jaw joint . because of this simpson ( 1959 ) suggested that it might better be classified as a mammal , but hopson and crompton retain it in the therapsida . although certain primitive features in the skull suggest a derivation from scaloposaurid bauriamorphs , indicating the posisbility that the mammalian condition may have evolved twoice ( once from advanced therocephalians via the ictidosaurs and once from cyndonts via tritylodonts ) but both the structure of the dentary and the braincase structure have independently confirm a cynodont ancestry , and the polyphyly of mammals is no longer considered a valid hypothesis .
pachygenelius stands truly at the dividing line between reptile and mammal in so far as this important diagnostic feature of jaw articulation is concerned . this is the only reason why the ictidosaurs are classified as reptiles rather than mammals . in the mammals , the quadrate and articular bones have migrated from the articular region of the jaw to the middle ear where they have been transformed into two of the bones concerned with the transmission of vibrations from the eardrum to the inner ear . because , in the ictidosaurs , the tta formation of the quadrate and articular bones had not taken place , these animals can be placed arbitrarily within the reptiles .
horizon : upper triassic ? , lower jurassic : stormberg series ( red beds and cave sandstone ) of south africa and lesotho ; los colorados formation of argentina . age : rhaetian / hettangian to sinemurian / early pliensbachian distribution : probably had a worldwide ( pangea ) distribution ecological community : anchisaur - plateosaur empire ecological niche / guild : small terrestrial insectivore modern equivalents : shrew , insectvore generally preferred food : mostly invertebrates , very small vertebrates length : about 10 or 20 cm long metabolism : endothermic potential predators : small theropod dinosaurs ( mostly coelophysidae ) , large sphenosuchid
lizards
, and protosuchid crodylomorphs ancestor : chiniquodontidae replaced : small chiniquodontidae replaced by : small mesozoic mammals descendents : class mammalia ( ancestral forms : sinoconodontidae , morganucodontidae , megazostrodontidae ) taxonomic status - valid family
red beds and cave sandstone ( middle and upper elliot formation ) , orange free state , south africa and lesotho .
from the early jurassic of nova scotia . but while it is not unlikely that this jaw might belong to
or a distinct but closely related species , probably a descendent . although a specific distinction may prove to be valid , it is doubtful that generic differences exist .
comments : the only known triassic trithelodont , and part of a highly endemic fauna , which makes it difficult to correlate . however although the los colorados formation is usually considered latest triassic ( late norian / rhaetian ) , jose bonparte says somewhere ( i can ' t find the exact passage . . . ) that the fauna may not be isochronous . so it is possible that the upper part of the los colorados may be hettangian ( earliest jurassic ) . that would fit in chaliminia with the other trithelodonts .
carroll , r . l . vertebrate paleontology and evolution . - w . h . freeman and company , new york , 1988
james a . hopson and herbert r . barghusen ,
an analysis of therapsid relationships
, in the ecology and biology of mammal - like reptiles ed . by nocholas hotton iii , paul d . maclean , jan j . roth and e . carol roth , smithsonian institute press , washington and london , 1986 , pp . 83 - 106
james a . hopson and james w . kitching , 1972 ,
a revised classification of the cynodonts ( reptilia ; therapsida ) , paleontologica africa , 14 . 17 - 85
trithelodont jaw - a fine photo of a partial jaw ( nova scotia museum ) . earliest jurassic ( early hettangian ) age .
' la importancia turistica de ischigualasto ' , preparado por dr william sill . a fossil inventory in spanish - at the bottom it lists chaliminia musteloides ( under
cynodont
unless otherwise attributed or quoted , all text is licensed under the creative commons license 1 . 0 and a 2 . 0 . this licence does not cover quoted material , and images , which are copyright their respective owners .
page by m . alan kazlev i am indebted to trevor dykes for helpful corrections and references . page uploaded 8 october 1999 . reposted and last modified 1 september 2005
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full reference : r . broom . 1912 . on a new type of cynodont from the stormberg . annals of the south african museum 7 : 334 - 336
see also carroll 1988 , kemp 1982 , martinelli and rougier 2007 and martinez et al . 1996
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warning : the ncbi web site requires javascript to function . more . . .
proc r soc lond b biol sci . 1980 jul 17 ; 208 ( 1173 ) : 461 - 81 .
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the tritheledontids , also and better known ( especuially in earlier literature ) as the ictidosaurs , were tiny latest triassic to early jurassic cynodonts that neatly bridge the gap between advanced theriodonts and the primitive mammaliforms .
the tritheledonts ( ictidosaurs ) are thus very advanced , probably insectivorous , cynodonts of small size in which some incisors and in some species the upper and probably postcanines have a transversely - oriented cutting edge , in others the uppers have an oblique and the lowers a longitudinal cutting edge . these are features connected , as in the tritylodonts , with the more efficient chewing of food . as in the chiniquodontidae the secondary palate is long ( so the animal could eat and breathe at the same time , a mammalian feature ) and the postorbital bar ( the bar of bone behind the eyes ) is absent , another feature found also in tritylodonts and primitive mammals .
but what makes these animals unique is the new mammalian joint between the squamosal and dentary had come into functional being . thus , the ictidosaur pachygenelius formerly known as diarthrognathus ) possesses both the reptilian quadrate - articular jaw joint and a newly developed mammalian squamosal - dentary jaw joint . because of this simpson ( 1959 ) suggested that it might better be classified as a mammal , but hopson and crompton retain it in the therapsida . although certain primitive features in the skull suggest a derivation from scaloposaurid bauriamorphs , indicating the posisbility that the mammalian condition may have evolved twoice ( once from advanced therocephalians via the ictidosaurs and once from cyndonts via tritylodonts ) but both the structure of the dentary and the braincase structure have independently confirm a cynodont ancestry , and the polyphyly of mammals is no longer considered a valid hypothesis .
pachygenelius stands truly at the dividing line between cynodont and mammaliform in so far as this important diagnostic feature of jaw articulation is concerned . this is the only reason why the ictidosaurs are classified outside the mammaliformes . in the mammaliforms , the quadrate and articular bones have migrated from the articular region of the jaw to the middle ear where they have been transformed into two of the bones concerned with the transmission of vibrations from the eardrum to the inner ear . because , in the ictidosaurs , this transformation of the quadrate and articular bones had not taken place , these animals are placed outside the mammaliformes . mak010421 .
characters : $ lack of pineal foramen [ rs01 ] ; $ posteriorly elongated secondary palate [ rs01 ] ; $ ribs ( laterally ? ) expanded [ rs01 ] .
links : eucynodontia ; synapsida - - the dinosauricon ; therapsida all treating probainognathia as a more inclusive clade ) .
small ( 3 - 6cm skulls ) carnivorous proto - mammals . cheek teeth broad , with prismatic enamel as in mammals ; teeth may have been double - rooted ; some teeth have transverse cutting edge , others the uppers have an oblique and the lowers a longitudinal cutting edge ; probably squamosal - dentary jaw joint and quadrate - articular joint both functional , with masseter and opposing muscles holding jaw in
sling
; postorbital and prefrontal absent ; frontal & palatine in contact ; temporal opening confluent with orbit ; postcranial skeleton said to be fully mammalian .
notes : [ 1 ] according to [ l + 02 ] the characters that support tritylodonts as the sister of mammaliforms are strongly localized to the orbital wall and sphenoid region . characters of the jaw joint , mandible and palate point to tritheledonts . atw020223 .
range : early jurassic of south africa , possibly north america . p . monus : red beds and cave sandstone ( middle and upper elliot formation ) , orange free state , red beds and cave sandstone ( middle and upper elliot formation ) , orange free state and lesotho , south africa , of hettangian to sinemurian age . p . broomi : clarens formation , orange free state , south africa , of sinemurian / early pliensbachian age .
image : pachygenelius jaw ( ~ 2 cm ) , parrsboro , nova scotia . from the nova scotia museum fossils of nova scotia website . © 1998 nova scotia museum and used by permission .
notes : [ 1 ] pachygenelius ? monus has also been reported from the early jurassic of nova scotia . but while it is not unlikely that this jaw might belong to pachygenelius ( or a similiar form ) , a species attribution , or even an unambigious genus attribution , is very unlikely . [ 2 ] diarthrognathus broomi is based on two juvenile specimens which are possibly , though not certainly , referable to p . monus . this then is either a synonym of the earlier p . monus or a distinct but closely related species , probably a descendent . although a specific distinction may prove to be valid , it is doubtful that generic differences exist . mak010421 . atw020601 .
range : late triassic to early jurassic of south america , los colorados formation , argentina , of late norian to hettangian age .
notes : the only known triassic tritheledont , and part of a highly endemic fauna , which makes it difficult to correlate . however although the los colorados formation is usually considered latest triassic ( late norian / rhaetian ) , jose bonparte says somewhere ( i can ' t find the exact passage . . . ) that the fauna may not be isochronous . so it is possible that the upper part of the los colorados may be hettangian ( earliest jurassic ) . that would fit in chaliminia with the other tritheledonts . mak010421 . atw020601 .
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universidade federal do rio grande do sul , porto alegre , brazil , paleovertebrate collection .
aus der späten trias ( caturrita formation ) vorgestellt . das neue material enthüllt wichtige informationen zur anzahl der incisiven , der grösse und form der canini , der morphologie des basicraniums und anderen aspekte von schädel und bezahnung . eine cladistische analyse mit berücksichtigung der neuen daten bestätigt die zuordnung von
sind drei untere incisiven mit einem vergrößerten ersten incisivus , untere und obere canini mit einer tiefen paracaninus - fossa am maxillare ; eine fast komplette obere und untere postcanine zahnreihe mit einem bezahnungsmuster vergleichbar mit dem anderer tritheledontiden ( z . b .
in der jugular - fossa , welche durch einen fingerartigen vorsprung der posterolateralen wandung des opistothicums voneinander getrennt werden ; sowie außerhalb der jugular - fossa liegene hypoglossale foramina .
ist ein schlüsseltaxon zum verständnis der frühen evolution der ictidosauriden , eine mit den mammaliformen nahe verwandte cynodontier - gruppe aus der oberen trias und dem unteren jura .
we thank luiz flávio lopes for the photographs of several specimens and cnpq for financial support ( tvo ) . the suggestions of the reviewers fernando abdala and zhe - xi luo and the editor oliver rauhut improved the quality of this paper .
character 2 . lower incisor number : from ? to 1 ( three incisors ) .
character 3 . some incisor enlarged : from ? to 1 ( present ) .
character 24 . sectorial postcanines with the major axis anteromedial - posterolaterally oriented , passing the distal portion of an anterior tooth medial to the mesial portion of the next tooth : from 0 to 1 ( present ) .
character 36 . postdentary bones : from ? to 1 ( reduced to narrow rod lying in postdentary trough ) .
character 68 . trigeminal nerve ( v 2 and v 3 ) exit : from ? to 1 ( foramen located entirely on the prootic , or on the anterior lamina of the petrosal ) .
character 69 . prootic and ophistotic : from ? to 0 ( unfused ) .
character 71 . fenestra ovalis : from ? to 0 ( with thickened ring ) .
character 74 . perilymphatic foramen separation from jugular foramen : from ? to 1 ( partially separated by finger - like projection from postero - lateral wall of jugular foramen ) .
character 76 . hypoglossal foramen : from ? to 1 ( separated from the jugular fossa ) .
; some clades are not diagnosed here ) . an asterisk ( * ) indicates ambiguous character - states
) : presence of some enlarged incisors ( ch . 3 ) , upper incisor 2 large and the others small ( ch . 4 ) , lower incisor 1 large and the other small ( ch . 5 ) , premaxilla forming the posterior border of incisive foramen ( ch . 39 ) * , length of palatine longer relative to maxilla in secondary palate ( ch . 47 ) .
) : dominant central bulbous main cusp on upper postcanines ( ch . 11 ) , upper posterior postcanines with cusp b and c buccally displaced and bulbous , prominent cusp a ( ch . 12 ) , lower middle and posterior postcanines with four cusps aligned decreasing in size posteriorly ( ch . 19 ) , posterior portion of secondary palate almost at the level of the tip of upper postcanine teeth , forming a deep groove between hard palate and tooth row ( ch . 48 ) .
unnamed clade . pachygenelinae ( clade 6 ) plus chalimininae ( clade 7 ) : single roots of postcanines ( ch . 25 ) , tooth row parallel to sub - parallel from the axial plane of the cranium ( ch . 30 ) , maxillary buccal shelf overhanging tooth row ( ch . 43 ) .
) : upper postcanines with buccal cingulum ( ch . 9 ) * , narrow upper postcanines with lingual cingulum ( ch . 10 ) * .
) : more than 11 upper postcanine teeth in adult ( ch . 8 ) * , absence of imbrincated sectorial postcanines ( ch . 24 ) * .
tritheledon plus diarthrognathus : absence of upper posterior postcanines with cusp b and c buccally displaced and bulbous , prominent cusp a ( ch . 12 ) * .
abdala , f . , and a . m . ribeiro . 2003 . a new traversodontid cynodont from the santa maria formation ( ladinian - carnian ) of southern brazil , with a phylogenetic analysis of gondwanan traversodontids .
abdala , f . , and a . m . ribeiro . 2010 . distribution and diversity patterns of triassic cynodonts ( therapsida , cynodontia ) in gondwana .
arantes , b . a . , m . b . soares , and c . l . schultz . 2009 .
( lepidosauria , sphenodontia ) do triássico superior do rio grande do sul : anatomia pós - craniana e relações filogenéticas .
bonaparte , j . f . , and m . c . barberena . 2001 . on two advanced carnivorous cynodonts from the late triassic of southern brazil .
( lepidosauria : rhynchocephalia ) from the upper triassic of rio grande do sul , brazil .
bonaparte , j . f . , j . ferigolo , and a . m . ribeiro . 1999 . a new early late triassic saurischian dinosaur from the rio grande do sul state , brazil .
bonaparte , j . f . , j . ferigolo , and a . m . ribeiro . 2001 . a primitive late triassic ‘ictidosaur’ from rio grande do sul , brazil .
bonaparte , j . f . , a . g . martinelli , and c . l . schultz . 2005 . new information on
bonaparte , j . f . , g . brea , c . l . schultz , and a . g . martinelli . 2007 . a new specimen of
bonaparte , j . f . , a . g . martinelli , c . l . schultz , and r . rubert . 2003 . the sister - group of mammals : small cynodonts from the late triassic of southern brazil .
bonaparte , j . f . , c . l . schultz , m . b . soares , and a . g . martinelli . 2008 . faxinal do soturno local fauna of the late triassic of rio grande do sul , brazil .
broom , r . 1912 . on a new type of cynodont from the stormberg .
n . g . n . sp . , a procolophonid reptile from the upper triassic of southern brazil .
crompton , a . w . 1958 . the cranial morphology of a new genus and species of ictidosaurian .
crompton , a . w . , and z . - x . luo . 1993 . relationships of the liassic mammals sinoconodon , morganucodon oehleri , and dinnetherium . in
, ed . f . s . szalay , m . j . novacek , and m . c . mckenna , 30–44 . new york : springer .
dias - da - silva , s . , e . v . dias , and c . l . schultz . 2009 . first record of stereospondyls ( tetrapoda , temnospondyli ) in the upper triassic of southern brazil .
furin , s . , n . preto , m . rigo , g . roghi , p . gianolla , j . l . crowley , and s . a . bowring . 2006 . high - precision u - pb zircon age from the triassic of italy : implications for the triassic time scale and the carnian origin of calcareous nannoplankton and dinosaurs .
goloboff , p . a . 1993 . “nona” , version 2 . 0 . program and documentation .
gradstein , f . m . , and j . c . ogg . 2004 . geologic time scale 2004–why , how and where next .
hillenius , w . j . 1992 . the evolution of nasal turbinates and mammalian endothermy .
hillenius , w . j . 1994 . turbinates in therapsids : evidence for late permian origins of mammalian endothermy .
hopson , j . a . , and h . barghusen . 1986 . an analysis of therapsid relationships . in
, ed . n . hotton iii , p . d . maclean , j . j . roth , and e . c . roth , 83–106 . washington dc : smithsonian institution press .
hopson , j . a . , and j . w . kitching . 2001 . a probainognathian cynodont from south africa and the phylogeny of nonmammalian cynodonts .
kermack , k . a . , f . mussett , and h . w . rigney . 1981 . the skull of
kischlat , e . - e . , and s . g . lucas . 2003 . a phytosaur from the upper triassic of brazil .
knoll , f . 2004 . review of the tetrapod fauna of the “lower stormberg group” of the main karoo basin ( southern africa ) : implications for the age of the lower elliot formation .
knoll , f . , and b . battail . 2001 . new ornithischian remains from the upper elliot formation ( lower jurassic ) of lesotho and stratigraphical distribution of southern african fabrosaurids .
lehrmann , d . j . , j . ramezani , s . a . bowring , m . w . martin , p . montgomery , p . enos , j . l . payne , m . j . orchard , w . hongmei , and w . jiayong . 2006 . timing of recovering from the end - permian extinction : geochronology and biostratigraphic constraints from south china .
( docodonta ; mammalia ) from the late jurassic of portugal and its implications to the evolution of mammalian characters .
liu , j . , and p . olsen . 2010 . the phylogenetic relationships of eucynodontia ( amniota : synapsida ) .
luo , z . - x . 1994 . sister - group relationships of mammals and transformations of diagnostic mammalian characters . in
, ed . n . c . fraser , and h . - d . sues , 98–128 . cambridge : cambridge university press .
luo , z . - x . 2007 . transformation and diversification in early mammal evolution .
luo , z . - x . , and a . w . crompton . 1994 . transformation of the quadrate ( incus ) through the transition from non - mammalian cynodonts to mammals .
luo , z . - x . , a . w . crompton , and s . g . lucas . 1995 . evolutionary origins of the mammalian promontorium and cochlea .
luo , z– . x . , z . kielan - jaworowska , and r . l . cifelli . 2002 . in quest for a phylogeny of mesozoic mammals .
luo , z– . x . , z . kielan - jaworowska , and r . l . cifelli . 2004 . evolution of dental replacement in mammals .
martinelli , a . g . , j . f . bonaparte , c . l . schultz , and r . rubert . 2005 . a new tritheledontid ( therapsida , eucynodontia ) from the late triassic of rio grande do sul ( brazil ) and its phylogenetic relationships among carnivorous non - mammalian eucynodonts .
martinez , r . n . , c . l . may , and c . a . forster . 1996 . a new carnivorous cynodont from the ischigualasto formation ( late triassic , argentina ) , with comments on eucynodont phylogeny .
muttoni , g . , d . v . kent , p . e . olsen , p . di stefano , w . lowrie , s . m . bernasconi , and f . m . hernández . 2004 . tethyan magnetostratigraphy from pizzo mondello ( sicily ) and correlation to the late triassic newark astrochronological polarity time scale .
bonaparte & barberena , 1975 ( probainognathia , therioherpetidae ) from the upper triassic of brazil .
cabrera 1943 en una sección triásica de brasil y su probable correlación con el mismo evento en la porción mediana superior de la formación ischigualasto ( triásico de argentina ) .
oliveira , t . v . , m . b . soares and a . g . martinelli . 2008 . new data on the late brazilian triassic tritheledontid cynodont
ovtcharova , m . , h . bucher , u . schaltegger , t . galfetti , a . brayard , and j . guex . 2006 . new early to middle triassic u - pb ages from south china : calibration with ammonoid biochronozones and implications for the timing of triassic biotic recovery .
rodrigues , p . g . 2005 . endotermia em cinodontes não - mamalianos : a busca por evidências osteológicas . unpublished m . sc . thesis , universidade federal do rio grande do sul , 133 .
rogers , r . r . , c . c . swisher iii , p . c . sereno , a . m . monetta , c . a . forster , and r . n . martínez . 1993 . the ischigualasto tetrapod assemblage ( late triassic , argentina ) and
rougier , g . w . , j . r . wible , and j . a . hopson . 1992 . reconstruction of cranial vessels in the early cretaceous mammal
rowe , t . 1988 . definition , diagnosis , and origin of mammalia .
schultz , c . l . , and m . b . soares . 2006 . proposta de nova denominação para a cenozona de ictidosauria , do triássico superior ( formação caturrita ) do rio grande do sul . in
shubin , n . h . , a . w . crompton , h– . d . sues , and p . e . olsen . 1991 . new fossil evidence on the sister - group of mammals and early mesozoic faunal distributions .
, a new tritheledontid from the lower elliot formation ( upper triassic ) of south africa .
soares , m . b . , j . f . bonaparte , and c . l . schultz . 2005 . new material of
soares , m . b . , and j . e . f . dornelles . 2009 . cinodontes , a chave para a origem dos mamíferos . in
, ed . a . a . s . da - rosa . santa maria : pallotti .
watson , d . m . s . 1913 . on a new cynodont from the stormberg .
wible , j . r . 1991 . origin of mammalia : the craniodental evidence reexamined .
wible , j . r . , and j . a . hopson . 1993 . basicranial evidence for early mammal phylogeny . in
, ed . f . s . szalay , m . j . novacek , and m . c . mckenna , 45–62 . new york : springer .
wu , x . - c . 1994 . late triassic - early jurassic sphenodontians from china and the phylogeny of the sphenodontia . in
, ed . n . c . fraser , and h– . d . sues , 38–69 . cambridge : cambridge university press .
zerfass , h . , e . l . lavina , c . l . schultz , a . j . v . garcia , u . f . faccini , and f . chemale jr . 2003 . sequence stratigraphy of continental triassic strata of southernmost brazil : a contribution to southwestern gondwana palaeogeography and palaeoclimate .
de oliveira , t . v . , martinelli , a . g . & soares , m . b . paläontol z ( 2011 ) 85 : 67 . urltoken
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non - mammalian cynodonts . the structure of the skull and jaws of a derived traversodon
should not be included in ictidosauria , nor should they considered to be a sister group to mammaliaforms .
specimen pvl2564 in right lateral and palatine skull views , and a medial view of the left lower jaw .
) . length of skull : 60cm . the signiﬁcant features of this specimen include
also extended to c . schultz and m . bento soares ( ufrgs ) for
cynodontia ) . proc r soc lond b biol sci . 208 : 461–481 .
stratigraphic and paleontological data . j south am earth sci . 55 : 123–132 .
it deals with the description of new probainognathian cynodonts , closely related to mammals , discovered in candelária and faxinal do soturno , rio grande do sul , brazil .
two new cynodonts ( therapsida ) from the middle - early late triassic of brazil and comments on south a . . .
we describe two new cynodonts from the early late triassic of southern brazil . one taxon , bonacynodon schultzi gen . et sp . nov . , comes from the lower carnian dinodontosaurus az , being correlated with the faunal association at the upper half of the lower member of the chañares formation ( ischigualasto - villa unión basin , argentina ) . phylogenetically , bonacynodon is a closer relative to . . . [ show full abstract ]
in this paper , the hypothesis of miniaturisation to explain the origin of mammals ( rowe 1993 , mammals phylogeny : mesozoic differentiation , multituberculates , monotremes , early therians , and marsupials . new york : springer - verlag , p . 129–145 ) is discussed , based on three lines of evidence resulting from new discoveries of eucynodonts in the late triassic of southern brazil ( bonaparte et al . . . . [ show full abstract ]
the genera of the brasilodontidae , protheriodon , brasilodon , brasilitherium , minicynodon and the indian panchetocynodon , are briefly summarised and the more significant evolutionary information from them is discussed . brasilodon and brasilitherium are possibly related to the origin of kuehneotheridae and morganucodontidae , respectively . a systematic rearrangement is proposed for the . . . [ show full abstract ]
a new cynodont from the santa maria formation , south brazil , improves late triassic probainognathian . . .
the fossil record of non - mammaliaform probainognathian cynodonts is outstanding in the late triassic rocks of brazil and argentina . approximately 15 genera are known , providing unique insights in the study of the major skeletal transformations prior to the mammalian condition . globally , the diversity of probainognathians is possibly under - represented , as the discovery of small - to . . . [ show full abstract ]
the discovery of a new upper triassic mammal ( erythrotherium parringtoni , gen . et sp . n . ) from the upper red beds of the stormborg series in basutoland is reported . the remains consist of an apparently complete , but crushed skull . no posteranial remains were found in association with the skull . a preliminary description of the internal view of the lower jaw and the outer view of one upper . . . [ show full abstract ]
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a relative of cynognathus , massetognathus was a plant - eating cynodont belonging to the traversodontid family . this cynodont lived in what is now south america , in brazil ( paleorrota ) and argentina ( los chañares formation ) during the middle triassic period ( 220 million years ago ) .
was about 50 centimetres ( 1 . 6 ft ) long . it had cheek teeth specially adapted to chewing on vegetation . it still had the distinctive long snout of its
instead they were flat - topped and were covered with a number of low ridges , which made them good for grinding any stems , roots and other plant materials .
palmer , d . , ed ( 1999 ) . the marshall illustrated encyclopedia of dinosaurs and prehistoric animals . london : marshall editions . p . 193 . isbn 1 - 84028 - 152 - 9 .
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. its membership was and is made up of both meat - eaters and plant - eaters . the chronological range extends from at least the lower
until the present day . this overview is concentrated on the proto - mammals , which are known from the lower triassic until the lower
. this was a wolf - sized predator , which had pretty much a worldwide distribution . about 90 % of its lower jaw was accounted for by a single , tooth - bearing bone called the
were differentiated , which enabled them to perform several functions ; tearing and chewing . a
tears at its prey , but it can’t chew . it’s an effective hunter , but a wasteful and messy eater . the ear of
by a joint called the articular - quadrate . the significance of these features and what happened next , is illustrated in a bit more detail below , ( see below : transitional fossils ) .
is the only known representative of a family called cynognathidae . however , various further derived relatives are also known .
further non - mammalian eucynodonts are known , though the structure followed here is probably in need of review . the main lineage of meat - eaters is the superfamily of chiniquodontoidea . i have this divided into two families , a further pair of possible families and some odd bits and pieces .
of south america . some more enigmatic material , ( mainly teeth ) , has been recovered from mid – upper triassic european strata . a middle triassic genus from africa ,
, has also been referred to this family , though this is seen as questionable by others . they ranged in size from tiny
dromatheriidae is a possible family based mainly on teeny teeth from the upper triassic of europe and north america , ( and perhaps india ) . although remains are sparse , these fossils are very mammal - like . a hypothesized ancestor of mammals could convincingly have been equipped with choppers like this , and some of this material may or may not represent our ancestors . it would require better
to test the validity of that possibility . it could be an informal grade rather than a natural
) . the status of this family has been differently interpreted by various researchers .
traditionally , the herbivoreous counterparts of the chiniquodontoids were grouped together under the term gomphodonts , ( ‘peg teeth’ ) . their chronological range extended from the lower
, and remains have been found on every continent in the world , with the exception of australasia . they’re also referred to as tritylodontoidea . it’s very likely that this arrangement is more a matter of convenience than systematics . however , as it is a convenient structure , let ' s take follow it .
the most basal representatives are found within a family called diademodontidae . most fossils come from the lower triassic of south africa . other reports stem from asia and perhaps antarctica .
somewhat more derived are the trirachodontids of africa , asia , russia and possibly north america . some were contemporaries of the diademodontids and the lineage seems to have survived until the middle triassic .
lived communally in warrens . this is known from several fossilized burrows preserved in south africa , along with their inhabitants .
the most diverse of the triassic gomphodonts are the members of traversodontidae . this family emerged during the lower triassic and continued until the end of that age . the original representatives were small , though later types reached lengths of 50cm or so . the most recent known remains come from near the end of the european
. these are teeth from shrew - sized animals . fossils have been found in all continents , ( excepting for australasia and antarctica ) , though the best remains are from the lower upper triassic strata of argentina and brazil , which seems to have been the heyday of the traversodonts .
possibly descended from the traversodonts is a family known as tritylodontidae . it’s fairly often assumed that non - mammalian
. where preserved , the anatomy suggests burrowing animals , and suitably sized fossilized burrows have been found at one location in colorado , along with tracks and anatomical remains . a post - cretaceous representative has some limited support , (
) , but this is more generally seen as some kind of mammal or other . tritylodonts were mammal - like in the extreme , and were usually classed as such until the 1920s . however , their anatomy maintained significant ‘reptilian’ features , especially in the
, when this family had a more or less worldwide distribution . ( one genus ,
, has been found in europe , china and north america . fragmentary tritylodont remains have also been recovered from antarctica . ) the most recent undisputed material comes from siberia and japan . the demise of the tritylodonts may be connected with the rise of
. there are a few genera dealt with here as mammals , which should possibly or probably be labelled as non - mammals . this is certainly the case for
. its dental replacement and growth habits weren’t mammalian . it probably also applies for
rock , ( carnian ) . it could also be the case for the members of haramiyida . however , other than for one exception , haramiyids are presently known only from tiny teeth . until more substantial remains turn up , the affinities of haramiyids is a matter beyond resolution .
and , when equipped with gnashers , have only one kind of tooth . however , as with
) ; the jaw joint is the articular - quadrate , ( it’s at least overwhelmingly dominant amongst the basal representatives ) .
became progressively more mammal - like , and the anatomical distinctions between the more derived forms and the earliest mammals , are best described as matters of degree .
grew in complexity and efficiency . the mammalian jaw - cranium joint ( dentary - squamosal ) grew up alongside of , and eventually , ( in
still worked with only one small bone , other important structural changes were underway ; eg . the cochlear canal appeared ( eg .
( this information has been derived from [ 1 ] mesozoic eucynodonts ; an internet directory . as that ' s my webpage , there are no issues of copyright . trevor dykes )
this article is from wikipedia . all text is available under the terms of the gnu free documentation license .