Orconectes yanahlindus Taylor, Rhoden & Schuster, 2016, new species
Creators: name: Taylor, Christopher A.
name: Rhoden, Cody M.
name: Schuster, Guenter A.
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Cambaridae
Orconectes
Orconectes yanahlindus

description: Orconectes yanahlindus, new species
Figs. 6, 7, Table 3
Diagnosis. Body and eyes pigmented. Rostrum slightly excavated, terminating in long acumen; weak median carina occasionally present (Fig. 6 J). Rostral margins thickened; margins straight, distal halves slightly converging, terminating in spines (Fig. 6 J). Areola length 35.4–47.0% (n=143, x =41.1, SD=1.5) of post orbital carapace length and 26.4–34.5% (n=143, x =30.5, SD=1.4) of total carapace length, narrowest part at midpoint, 4.0–12.8 (n=143, x =7.3, SD=1.67) times as long as wide with two to six punctuations (n=143, x =3.2, SD=0.7) across narrowest part. One corneous cervical spine on each side of carapace. Postorbital ridges well defined, ending in corneous spines (Fig. 6 A). Suborbital angle obtuse. Antennal scale broadest at midlength, thickened lateral margin terminating in large corneous spine (Fig. 6 L). Ischia of third pereiopods of males with hooks; hooks overreaching basioischial articulation in form I males only.
Chela with two rows of tubercles along mesial margin of palm, usually 6–11 (n=119, x =8.1, SD=1.1) tubercles in mesial most row and 6–12 (n=119, x =8.2, SD=1.0) in dorsomesial (second) row; usually setae on dorsomedian surface of fixed finger (Fig. 6 M). Three spines present on ventral surface of carpus; distomedian spine on the ventral surface of the carpus large and corneous.
Mandible with serrated incisor region. Cephalomedian lobe of epistome triangular; epistomal zygoma ridged and weakly arched (Fig. 6 H).
First pleopods of form I male symmetrical, extending to posterior edge of bases of first pereiopods when abdomen flexed. First pleopod of form I male with shoulder on cephalic surface at base of central projection; central projection corneous, constituting 50.0%–57.1% (n=36, x =53.4, SD=1.9) of total length of first pleopod, straight or very slightly arched caudodistally and tapering to a pointed tip; mesial process non-corneous, constituting 36.1%–48.6% (n=36, x =41.2, SD=3.1) of total length of first pleopod, straight and tapering to a pointed tip (Figs. 6 B–E). Gonopod of form II male non-corneous, extending to posterior edge of bases of first pereiopods when abdomen flexed; central projection straight, mesial projection straight and subequal in length; both elements tapering to rounded tips (Figs. 6 F–G). Annulus ventralis immovable, subcircular; dorsal end with wide median trough, fossa centered and dorsolaterally flattened; sinuate sinus running from top of fossa to bottom edge (Fig. 6 K).
Description of Holotypic Male, Form I. Body slightly compressed dorsoventrally, carapace slightly wider than abdomen (17.0 mm and 15.7 mm, respectively). Greatest width of carapace larger than height at caudodorsal margin of cervical groove (17.0 mm and 13.9 mm, respectively). Postorbital carapace length (26.0 mm) 77.0% of length of carapace. Areola 9.3 times longer (11.1 mm) than wide (1.2 mm) with two punctuations across narrowest part; length of areola 32.8% of total carapace length. Rostrum densely covered with punctations, slightly excavated, median carina absent; margins thickened, distal halves straight and slightly converging, ending in small rounded corneous spines. Acumen terminating in upturned corneous rounded spine and reaching just past distal end of antennular peduncle. Postorbital ridges well developed, terminating in rounded corneous spines. Suborbital angle absent. Cervical spines corneous; branchiostegal areas of carapace densely punctate, dorsal surface scattered with punctations.
Abdomen longer than carapace (38.3 mm and 33.8 mm, respectively). Cephalic section of telson with one movable and one immovable spine in each caudolateral corner. Protopodite of uropod with spine extending over endopodite and spine in caudolateral corner extending over exopodite. Caudal margin of cephalic section of exopodite with numerous fixed spines (n=16). Cephalic and caudal sections of exopodite with prominent median ridge. Lateral margin of endopodite with prominent median ridge terminating in spine; endopodite with prominent median ridge terminating in premarginal spine. Dorsal surfaces of telson and uropods setiferous.
Antennal scale broadest at midlength, thickened lateral margin terminating in large corneous spine. Right antennal scale 7.4 mm long, 3.1 mm wide.
Mesial surface of palm of right chela with two rows of tubercles, 10 tubercles in mesial most row, nine tubercles in dorsomesial row, and four tubercles located lateral to distal end of dorsomesial row. Mesial and lateral surfaces of chela scattered with setiferous punctations; ventral surface with scattered punctations. Dorsal surfaces of fingers of chela with longitudinal ridges flanked on both sides by rows of setiferous punctations. Opposable margin of propodus with six well developed tubercles, third and fourth from base largest. Opposable margin of dactyl with nine well developed tubercles of uniform size. Finger of propodus and dactyl with well developed corneous tips at terminal ends.
Carpus with deep oblique furrow dorsally; mesial margin with one large corneous procurved spine at midpoint and one small corneous spine along distomesial margin; ventral surface with one corneous spine at midpoint of distal margin, distolateral corner enlarged and globular with one small corneous spine. Dorsodistal surface of merus with two corneous spines; ventromesial margin with one row of 11 angled tubercles, second and third from base smaller than remaining tubercles, terminating in one large corneous spine; vertrolateral margin with two large spines at distal end. Ventral surface of ischium with one small corneous spine at its base.
Hook on ischia of third pereiopods only; hook simple, overreaching basioischial articulation and opposed by low rounded tubercle on base. First pleopod as in Diagnosis above, central projection constituting 54.2% of total length of first pleopod.
Description of Allotype, Female. Differing from holotype as follows. Areola 6.7 times longer than wide with five punctuations across narrowest part. Postorbital carapace length 76.4% of total length of carapace. Mesial row of tubercles along palm of right chela with nine tubercles; dorsomesial row with nine tubercles. Tufts of setae along base of finger of propodus. Opposable margin of finger of propodus with five tubercles. Opposable margin of dactyl with six large tubercles. Dorsodistal margin of merus with six small corneous tubercles. Ventromesial margin of right merus with one row of 10 spines, terminating in one large corneous spine, three basalmost spines non-corneous. Ischia of third pereiopods lacking hooks.
Sternum between third and fourth pereiopods narrowly V-shaped. Postannular sclerite raised and not as wide as annulus ventralis. First pleopod uniramous, reaching to center of annulus when abdomen flexed.
Description of Morphotype, Male, Form II. Differing from holotype as follows. Areola constituting 31.0% of length of carapace and 8.9 times longer than wide; with four punctations across its narrowest part. Postorbital carapace length 75.7% of length of carapace. Mesial row of tubercles along palm of right chela with nine tubercles, dorsomesial row with eight tubercles. Opposable margin of propodus with five well developed tubercles, opposable margin of dactyl with six. Ventromesial margin of merus with 12 angular turbercles.
Ischia of third pereiopods with low rounded bump at their bases, bumps not overreaching basioischial articulation. First pleopod as described in Diagnosis.
Size. Largest specimen examined is a 47.3 mm TCL female (n=143). Females (n=54) range in size from 21.1 mm to 47.3 mm TCL. Form I males (n=36) range in size from 19.2 mm to 41.71 mm TCL. Form II males (n=53) range in size from 17.1 mm to 42.0 mm TCL.
Color (Fig. 7). Base color of dorsal and lateral surfaces of chela and chephalothorax tan to olive green. Dark mandibular adductor insertion scars and dorsal saddle just anterior of cervical groove. Dark to olive green band just anterior of caudal ridge. Dorsal surfaces of abdomen segments and tail fan variable, ranging from light tan to mottled olive green. Each abdominal segment with a pair of small dark rectangles at anteriodorsal edge and single dark wedge-shaped patches in each cephalolateral corner. Dorsolateral surfaces of abdominal segments usually with cream colored spots, spots may be very light to absent in some specimens in the Tennessee portion of the species’ range (Fig. 7 F). Dark spots on dorsal surface of chelae at base of propodus and dactyl usually present, spots may be so light that they are undetectable in some specimens (Fig. 7 A, 7F). Tubercle at chela/carpus articulation joint, tubercles long mesial margin of chela palm and dactyl, and spines on carapace and merus cream colored. Fingers of chelae with orange tips followed proximally by wide black bands. Dorsal surfaces of pereiopods with alternating dark and light tan to olive green patches. Ventral surfaces of cephalothorax and abdomen cream.
Type locality. Big Creek at State Road 99 bridge crossing, Limestone County, Alabama (34.8519°N, - 87.0416°W NAD 83). The creek flows along the southern edge of a residential community, 4.8 km northeast of Oakland, Alabama. Big Creek averages approximately 2–3 m in width at low flow conditions and substrate is dominated by gravel and scattered cobble in shallow riffle areas and finer sediments in pool reaches. Both sides of the creek are tree-lined. Row crop occurred immediately southeast and southwest of the riparian corridor near the type locality. The holotype and allotype were collected under rocks or cobble.
Disposition of types. The holotype, allotype, and morphotype are deposited in the Illinois Natural History Survey Crustacean Collection (INHS 15453, INHS 15454, and INHS 15452 respectively), as are the following paratypes; 3 ♂ I, 3 ♂ II and 6 ♀ (INHS 11865). Paratypes consisting of 12 ♂ I, 4 ♂ II, and 10 ♀ (USNM 206678) and 2 ♂ I, 4 ♂ II, and 8 ♀ (USNM 145856) are deposited at the National Museum of Natural History, Smithsonian Institution, Washington, D.C.
Range. Orconectes yanahlindus is confined to the lower Tennessee River drainage in the Highland Rim physiographic province of southcentral Tennessee and northern Alabama (Fig. 2). Streams in this physiographic province are generally higher gradient with chert gravel or fractured limestone substrates and occur in narrow valleys draining surrounding ridges. Within the Tennessee River drainage, the species is known to range from the middle Elk River drainage near Winchester, TN down to the Buffalo River drainage (Duck R. dr.) in Perry Co., Tennessee.
A total of 143 specimens has been examined from 58 locations in southern Tennessee and northern Alabama. Museum collection numbers and counties of these 58 sites are listed in the Material Examined section, below.
Habitat, life history. Streams in the Highland Rim usually drain limestones and chert and some shales and are characterized by cherty gravel, sand, and some bedrock substrates. Gradient is generally moderate and water within the streams are clear with moderate to low productivity (Etnier and Starnes 1993). Within streams in its range, O. yanahlindus is normally found under pieces of cobble or large gravel in areas with flow. The species can also occasionally be encountered in isolated woody debris piles in areas with flow. We are in possession of only two ovigerous females of O. yanahlindus, one collected on 31 March 1967 and the other on 21 April 1969. These two records suggest that the species follows the typical pattern seen eastern North American members of the genus Orconectes of hatching young during the spring months. All other aspects of the life history of O. yanahlindus are unknown.
Etymology. yanahlindus L. = yanahli, Chickasaw for “to flow”, in reference to the areas of streams with water flow where the species is encountered. Named in honor of the Chickasaw, an indigenous people of the southeastern United States. For a long period of their history during the pre-European settlement and colonial years, the Chickasaw mostly inhabited regions of the lower Tennessee River drainage that overlap with the known range of O. yanahlindus.
Crayfish associates. The following species were collected from habitats containing O. yanahlindus: Barbicambarus simmonsi Taylor and Schuster, 2010, Cambarus (Lacunicambarus) acanthura Hobbs, 1981, Cambarus (Cambarus) bartonii (Fabricius, 1798), Cambarus (Hiaticambarus) girardianus Faxon, 1884, Cambarus (Depressicambarus) graysoni (Faxon, 1914), Cambarus (Depressicambarus) striatus Hay, 1902, Orconectes (Trisellescens) alabamensis (Faxon, 1884), Orconectes (Gremicambarus) compressus (Faxon, 1884), Orconectes (Procericambarus) durelli Bouchard and Bouchard, 1995, Orconectes (Procericambarus) forceps (Faxon, 1884), Orconectes (Procericambarus) mirus (Ortmann, 1931), Orconectes (Procericambarus) placidus (Hagen, 1870), Orconectes (Gremicambarus) validus (Faxon, 1914), and Procambarus (Ortmannicus) acutus (Girard, 1852).
Variation. In addition to the range of ratios and counts given in the Diagnosis section and the straight to slightly arched central projection of the form I male first pleopod, other morphological variations in O. yanahlindus include the following. The distolateral corner of the ventral surface of the carpus is not enlarged in some individuals. Some individuals have one spine instead of two on the dorsodistal surface of the merus. In some individuals there is variation in the position of the largest tubercle on the opposable margin of propodus. Some form I males harbor a flattened, sometimes upturned mesial process of the first pleopod. Some individuals lack the spine found on the distomedian ventral surface of the carpus. Some aspects of color pattern across this species’ range is variable and are described in the Color section.
Comparisons. Of Orconectes (Procericambarus) members found in the Eastern Highlands and central Ohio River drainage, Orconectes yanahlindus, new species is most similar to O. ronaldi, O. cristavarius, O. spinosus, and O. putnami as recognized herein by possessing a central projection of form I male first gonopod that comprises 45% or more of the total length of the first gonopod, a dentate incisor region on the mandible and lacking a strong median carina on the dorsal surface of the rostrum. While some populations of O. cristavarius in the Kentucky, Cumberland, upper Big Sandy, and upper Licking river drainages lack a median carina (Taylor 2000), and a few O. yanahlindus possess a weak carina, O. yanahlindus differs from that species, and O. ronaldi, in having a longer central projection relative to the total length of the first gonopod. Orconectes yanahlindus possess a form I central projection that is at least 50% of the total length of the entire first gonopod (x =53.4, SD=1.9) while in both O. ronaldi (x =45.0, SD=2.0) and O. cristavarius (x =47.0, SD=2.5) the central projection is less than 50%. Orconectes yanahlindus differs from O. putnami and O. spinosus in the characters described in the preceding Discussion section.
Relationships. We feel that Orconectes yanahlindus most closely related to other members of the OJSC given its range and possession of a long form I first pleopod elements. Single morphological character state differences separate many of the species in OJSC, thus making species-level relationships within the group difficult to hypothesize given our current understanding of morphological character variation across species. Until the formation of an evolutionary hypothesis based on multiple independent molecular characters such as nuclear and mitochondrial gene regions is proposed, we refrain from proposing sister species- and clade-level relationships for species within the OJSC.
Suggested Vernacular name. The Spinywrist Crayfish, in reference to the strong distomedian spine found on ventral surface of the carpus.
Conservation status. Given O. yanahlindus’ s range across a significant portion of the middle Tennessee River drainage and the lack threats from non-native crayfishes and habitat alteration, we recommend a status of Currently Stable following the criteria of the American Fisheries Society as outlined by Taylor et al. (2007). These same factors warrant a classification as Least Concern following the criteria of the International Union for the Conservation of Nature (IUCN).
Material examined. Number, sex, and form of specimens examined are in parentheses. MI = form I male, MII = form II male, F = female.
Orconectes spinosus. ALABAMA: Shelby County: INHS 11857 (1 MII, 1 F). GEORGIA: Floyd County: USNM 129181 (I MI), USNM 147738 (1 MI, 1 F). Murray County: INHS 8809 (1 MI), INHS 8901 (1 F), USNM 130741 (3 MI, 2 F), USNM 130748 (3 MI). Murray/Whitfield Counties: USNM 177132 (6 MI). Whitfield County: INHS 8900 (1 MII, 1 F), USNM 1 30733 (5 MI, 1 F), USNM 130736 (4 MI), USNM 130742 (7 MI, 1 F). TENNESSEE: Bradley County: USNM 206656 (2 MI). Polk County: USNM 217398 (4 MI).
Orconectes putnami. INDIANA: Perry county: INHS 9206 (2 MI, 1 F). KENTUCKY: Barren County: INHS 8838 (4 MI). Breckinridge County: INHS 6750 (4 MI), INHS 8429 (3 MI, 1 F), INHS 8440 (4 MI), INHS 9207 (1 MI, 1 F). Butler County: INHS 6848 (4 MI). Grayson County INHS 8345 (3 MI, 1 F). Logan County: INHS 4864 (1 MI). Wayne County: INHS 6195 (2 MI, 1 F), INHS 7036 (4 MI). Wayne/ McCreary Counties: INHS 7034 (4 MI), INHS 7040 (3 MI, 1 F), INHS 7046 (3 MI, 1 F), INHS 7048 (4 MI).
Orconectes yanahlindus. ALABAMA: Colbert County: INHS 11175 (2 MI, 2 F). Cullman County: INHS 11834 (1 MII). Lauderdale County: INHS 4436 (1 MII), INHS 4 987 (1 MII, 2 F), INHS 5000 (1 MII, 2 F), INHS 11371 (2 MI, 1 F), INHS 11386 (3 MII, 1 F), INHS 11859 (2 F), INHS 11864 (1 MII, 2 F), INHS 1 1865 (2 MI, 2 F), INHS 11886 (1 MI), INHS 11889 (1 MII, 3 F), INHS 1 2002 (1 F), INHS 12007 (1 MI), INHS 12017 (3 F), INHS 13175 (2 MI, 1 MII), USNM 145 856 (2 MI, 1 MII, 1 F), USNM 132187 (3 MI, 1 F). Lawrence County: INHS 11831 (1 MII), INHS 11839 (1 MII), INHS 11988 (1 MI, 1 F). Limestone County: INHS 32 (1 MI, 2 F), INHS 11841 (1 MII), INHS 11 842 (1 MII), INHS 11 850 (3 MI, 1 F), INHS 11858 (3 MI, 1 F), INHS 11867 (4 MII), INHS 11 869 (1 MII), INHS 11 888 (2 MI, 2 F), USNM 132597 (4 MI). Madison County: INHS 11840 (1 MII), USNM 206678 (4 MI). Morgan County: INHS 9 (2 MII, 2 F), INHS 11833 (2 MII), INHS 11853 (3 MII), INHS 11868 (1 MI, 3 MII). TENNESSEE: Franklin County: USNM 177440 (1 MII). Giles County: INHS 9807 (1 MII), INHS 1 3183 (1 MI, 1 MII, 1 F), USNM 1 45718 (2 MI, 1 F). Hardin County: INHS 5762 (1 MI, 3 MII), Lawrence County: INHS 4491 (1 MII), INHS 4941 (1 MI, 2 MII), INHS 4943 (1 MII), INHS 4 982 (2 MII), INHS 5057 (1 MII), INHS 9820 (2 MII, 2 F), INHS 9832 (1 MII), INHS 11 326 (1 F), INHS 11614 (1 MI). Lewis County: INHS 4425 (1 MI, 4 F), INHS 5761 (2 MI, 1 MII). Perry County: USNM 144385 (1 MI). Wayne County: INHS 898 (4 MII), INHS 4427 (1 F), INHS 4428 (1 MI, 1 MII, 1 F), INHS 9008 (1 MII, 1 F), INHS 11329 (1 MII, 2 F).
Revised key to species of the O. juvenilis Complex (Total first pleopod length measured on form I males from proximomesial edge of the gonopod just below the proximomesial boss and directly inline with the central projection to the distal tip of the central projection [Fig. 1]).
1 Incisor region of one or both mandibles with straight edge.....................................................2
1’ Incisor region of both mandibles not straight, both with distinct teeth.............................................5
2 Center of rostrum with median carina......................................................................3
2’ Center of rostrum without median carina...................................................................4
3 Central projection of first pleopod straight..................................................... O. theaphionensis (known from East Fork of White River dr. in southcentral Indiana)
3’ Central projection of first pleopod with curved tip................................................... O. raymondi (known from tributaries of the Ohio River in Brown and Adams cos., Ohio)
4 Form I male first pleopod long, central projection at least 45% of total length of pleopod, pleopods usually reaching base of first pair of pereiopods with abdomen flexed forward................................................. O. juvenilis (known from lower Kentucky, Rockcastle [Cumberland R. dr.], Salt, and Ohio River drainages in northcentral Kentucky and southeastern Indiana, possibly introduced into the upper Tennessee River drainage in extreme eastern Tennessee [Kessler et al. 2015] and in France)
4’ Form I male first pleopod shorter, central projection less than 45% of total length of pleopod, pleopods not reaching base of first pair of pereiopods with abdomen flexed forward................................................. O. rusticus (known natively from the Ohio River drainage in western Ohio, eastern Indiana, and northern central Kentucky, possibly introduced in Maumee River drainage of northwestern Indiana and southeastern Michigan; widely introduced into other regions of the Northeastern and Midwestern United States and Canada)
5 Ventral surface of carpus without strong distomedian spine, a low rounded tubercle may be present............. O. putnami (known from the Cumberland, Green, and Ohio River drainages in central Kentucky and northcentral Tennessee)
5’ Ventral surface of carpus with distomedian spine............................................................ 6
6 Form I male first pleopod with central projection less than 50% of total length of first pleopod........................7
6’ Form I male first pleopod with central projection equal to or greater than 50% of total length of first pleopod.............8
7 Central projection of form I male first pleopod arched caudodistally, its tip overhanging tip of mesial process; posterior edges of abdominal segments and lateral edges of chelae orange or red in life................................ O. cristavarius (known from upper Cumberland River drainage in southeastern Kentucky east to the New River drainage of western North Carolina and Virginia; also in portions of the extreme headwaters of the James River drainage of Virginia, Elk River drainage of West Virginia and the extreme upper Tennessee River drainage in western Virginia)
7’ Central projection of form I male first pleopod straight, it’s tip not overhanging tip of mesial process; posterior edges of abdominal segments and lateral edges of chelae not orange or red in life................................... O. ronaldi (known from the Mud River and Muddy Creek drainages of westcentral Kentucky, possibly introduced into the upper Tennessee River drainage in extreme eastern Tennessee [Kessler et al. 2015])
8 Form I first pleopods longer, constituting at least 46% of carapace length; areola usually less than 30% of carapace length............................................................................................... O. spinosus (known from the upper Coosa River drainage in northwestern Georgia and southeastern Tennessee)
8’ Form I first pleopods shorter, constituting 45% or less of carapace length; areola length usually 30% or greater than carapace length.................................................................................... O. yanahlindus (known from the middle Tennessee River drainage in northern Alabama and southwestern Tennessee)
description: Published as part of Taylor, Christopher A., Rhoden, Cody M. & Schuster, Guenter A., 2016, A new species of crayfish in the genus Orconectes (Decapoda: Cambaridae) from the Tennessee River Drainage with comments on and key to members of the O. juvenilis Species Complex, pp. 161-175 in Zootaxa 4208 (2) on pages 168-174, DOI: 10.11646/zootaxa.4208.2.4, http://zenodo.org/record/203846