Paguristes Dana 1851, n. sp.
Creators: name: Komai, Tomoyuki
name: Reshmi, Rema
name: Kumar, Appukuttannair Biju
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Diogenidae
Paguristes

description: Genus Paguristes Dana, 1851
Paguristes luculentus n. sp. (Figs. 1–7)
Material examined. Holotype: male (sl 12.1 mm), off Kollam, Kerala State, India, 08°34'24.85"N, 76°20'25.32"E, 100–110 m, 21 November 2012, commercial trawl, ZSI/ WGRC /IR/INV.4148.
Paratypes: 1 male (sl 10.5 mm), same data as holotype, CBM-ZC 12589; 1male (sl 11.9 mm), same data, DABFUK-AR-AN 95.
Description. Thirteen pairs of deeply quadriserial gills.
Shield (Fig. 1 A) about 1.2 times as long as wide; rostrum narrowly triangular, usually distinctly overreaching lateral projections and overreaching midlength of ocular acicles; lateral projections broadly triangular, with or without marginal spinule; anterior margin between rostrum and lateral projections evenly concave; anterolateral margins sloping; lateral margins slightly convex; dorsal surface with granules and several tufts of moderately short to long setae laterally; gastric elevations clearly delimited, rugose and punctate. Anterodorsal portion of branchiostegite well calcified, with row of minute denticles or spinules on dorsal and anterior margins (Fig. 1 D). Posteromedian plate (Fig. 1 B) well calcified, noticeably narrowed posteriorly.
Ocular peduncles (Fig. 1 A) relatively slender, subequal or slightly unequal (left longer than right), 0.7 times as long as shield, slightly inflated basally, bearing longitudinal row of tufts of moderately long setae dorsomesially; corneas not dilated, slightly wider than basal width of ocular peduncle, corneal diameter less than 0.2 of peduncular length. Ocular acicles triangular, each terminating in simple, sharp spine.
Antennular peduncles (Fig. 1 A, C) just reaching or slightly overreaching distal corneal margins; basal segment with small spine on distolateral margin of statocyst lobe, ventrodistal margin produced and terminating in sharp spine partially obscured by tuft of long setae; penultimate segment unarmed on ventral margin; ultimate segment about 1.4 times as long as penultimate segment. Dorsal flagellum slightly shorter than ultimate peduncular segment.
Antennal peduncles (Fig. 1 A, D) reaching corneal bases, but not reaching distal corneal margins; first segment unarmed on lateral face, ventromesial distal angle produced into rounded process; second segment with dorsolateral distal angle produced, terminating in bifid spine, dorsomesial distal angle with small spine, mesial half of dorsal surface not particularly elevated; third segment with strongly produced, sharply pointed ventromesial distal angle; fourth segment with minute spine at distolateral angle; fifth segment moderately slender, unarmed. Antennal acicle moderately slender, slightly falling short of distal end of fifth peduncular segment, terminating in simple or bifid spine, mesial margin with row of 4–6 small spines, lateral margin with 3 or 4 similarly small spines. Antennal flagellum (Fig. 1 E) slightly exceeding twice length of shield, consisting of more than 60 articles, each article with several short setae on distal margin (at most 2.5 times as long as one article).
Third maxilliped (Fig. 2 A) moderately slender; carpus with minute dorsolateral distal and ventrolateral distal spinules; merus with row of 5 small spines on ventrolateral margin, but unarmed on dorsodistal margin; ischium with small ventrodistal spine, and with well-developed crista dentata consisting of row of sharp triangular corneous teeth; coxa with 2 spinules at ventrodistal angle. Exopod slightly overreaching distal margin of carpus.
Chelipeds slightly unequal, somewhat dissimilar (left stouter); armature and setation generally similar; spines on palms and carpi mostly corneous-tipped. Left cheliped (Fig. 3 A–E) with propodal/carpal articulation rotated counterclockwise about 15° from horizontal. Chela subtriangular in dorsal view, about 1.7 times as long as wide. Dactylus1.6 times as long as palm, slightly curved ventrally; dorsomesial margin bluntly delimited by double row of small spines, dorsal surface with numerous scattered small spines decreasing in size distally and sparse short setae; mesial face shallowly depressed proximally, covered with closely set numerous small spines becoming blunt and smaller ventrally, continuing to ventral surface; cutting edge with row of small blunt calcareous teeth in proximal 0.7 (proximalmost 2 teeth prominent, molariform; 1–3 tiny corneous teeth interspersed by these calcareous teeth) and row of small, partially fused corneous teeth in distal 0.3, terminating in small corneous claw; inner surface below cutting edge broad, somewhat concave, with row of small rounded teeth or tubercles on ventral margin; no hiatus between dactylus and fixed finger when closed. Palm with row of spines on dorsomesial margin (these spines not particularly strong, though still stronger than those on dorsal surface of palm), slightly convex dorsal surface with covering of scattered small spines and short sparse setae, dorsolateral margin bluntly delimited by double or triple row of small spines extending onto fixed (these spines directed laterally); lateral face of palm and fixed finger broadly concave around base of fixed finger, with scattered corneous-tipped tubercles diminishing in size distally; mesial face of palm sloping to ventral surface, with numerous scattered small tubercles becoming smaller and lower ventrally and tufts or individual very short setae; ventral surface generally convex, with small to large corneous-tipped tubercles arranged in 3 irregular rows along mesial concavity and sparse tufts of short to long setae. Fixed finger very slightly curved ventrally; cutting edge with row of closely spaced, blunt calcareous teeth interspersing minute corneous teeth; inner surface below cutting edge also broad, concave, with row of rounded tubercles on ventral margin and tufts of long setae. Carpus with row of moderately strong spines on dorsomesial margin, dorsolateral margin not delimited; dorsal and lateral surfaces with numerous, scattered minute to small spines and tufts of short setae not obscuring armature, ventrolateral distal angle with small spine; mesial face with several small spines or tubercles in dorsal half, otherwise almost smooth; ventral surface shallowly depressed, distal margin weakly tuberculate. Merus triangular in cross section, with row of multifid spines on dorsal margin, decreasing in size and becoming obsolete proximally; subdistal transverse groove delimited proximally by row of small spines or multifid tubercles; distal margin with row of small spines, dorsal spines strongest; lateral face with scattered tiny multifid tubercles or simple granules and tufts or individual short setae; mesial face nearly smooth; ventral surface with armature including scattered numerous minute to small spines becoming larger laterally and prominent low protuberance at proximomesial portion, and with numerous tufts of long setae. Ischium with row of denticles on ventromesial margin; laterodistal margin minutely denticulate. Coxa with patch of spinules on ventral surface posteriorly.
Right cheliped (Fig. 4 A–D) without noticeable rotation of propodal/carpal articulation. Chela elongate subovate in dorsal view, about 2.3 times as long as wide. Dactylus 1.9 times as long as palm. Palm somewhat compressed laterally; dorsomesial margin with row of strong spines; lateral surface perpendicular, faintly concave entirely. Merus with trace of protuberance on proximomesial portion of ventral surface.
Second pereopods (Figs. 5 A) moderately slender, similar from right to left, right overreaching tip of right cheliped by 0.7 length of dactylus; spines mostly corneous-tipped. Dactyli 1.7 times as long as propodi, 7.7 times as long as wide, gently arcuate but not twisted, terminating in small corneous claw; dorsal margins each with row of moderately long, bristle-like setae and row of small spines in proximal half mesial to setal row (Fig. 6 A); lateral surfaces convex transversely, with scattered minute individual setae and tufts of short stiff setae; mesial surfaces each with sets of 2 or 3 short bristle-like setae adjacent to dorsal margin, tiny spines arranged in several irregular longitudinal rows (these spines erect or forwardly curved) and tufts of stiff setae adjacent to ventral margin (Fig. 6 A, B); ventral margins each with more than 50 minute, slender corneous spinules becoming more widely spaced proximally (Fig. 6 A, B). Propodi each with single row of prominent spines and tufts of short stiff setae on dorsal margin; lateral faces each with row of smaller spines and tuft of stiff setae adjacent to dorsal row of spines and median row of tufts of setae; mesial faces each with small spines, arranged in irregular 2 rows, adjacent to dorsal row of spines, and sparse minute to small row protuberances bearing very short setae (Fig. 6 B); ventral surfaces each with sparse scale-like, corneous spines and few short setae. Carpi each with row of moderately strong spines on dorsal margin; lateral faces each with faint, sinuous sulcus and row of tufts of short setae along midline, and some additional tiny to small spines adjacent to dorsal spines; mesial faces (Fig. 6 C) also with some additional small spines adjacent to dorsal spines, otherwise unarmed, almost glabrous; ventral surfaces each with some minute spinules. Meri strongly compressed laterally, with tufts of setae on dorsal margins, arising from very low protuberances; lateral faces with sparse tufts of short setae; mesial faces nearly glabrous, only with few tufts of setae; ventral margins each with double rows of small spines and tufts of long setae mesially (Fig. 6 D). Ischia unarmed, with numerous setae on dorsal and ventral margins. Ischia with few small spines or tubercles and tufts on setae on dorsal margin; ventral margin with row of tiny spines mesial to fine row of long setae (Fig. 6 D). Coxae with few minute spinules on anteromesial angles.
Third pereopods (Fig. 5 B) similar from right to left, somewhat differing from second pereopods mainly in armature. Dactyli somewhat twisted, thus ventral corneous spinules hardly visible in lateral view; dorsal margin without conspicuous spines (Fig. 6 E); mesial faces each with row of short spiniform setae (setae in proximal half usually paired) and sets of 2 or 3 short to long bristle-like setae becoming longer and more narrowly spaced distally and minute, stout corneous spines in proximal half adjacent to ventral margin (Fig. 6 E). Propodi each with low, marginally spinose or denticulate protuberances and tufts of short setae on dorsal surface; mesial surfaces each with sparse, minute, scale-like, corneous spines (Fig. 6 F). Carpi each with double row of small spines diminishing in size proximally on dorsal margin mesially (Fig. 6 F). Meri unarmed or armed with few minute spinules on ventral margin. Ischium without conspicuous spines on ventral margin.
Fourth pereopods (Fig. 2 B) each with prominent, rod-like preungual process (not reaching beyond terminal claw) followed by row of several corneous teeth on ventral margin of dactylus. Propodal rasp consisting of at most 4 rows of rounded corneous scales beyond midlength of ventral margin. Carpi without dorsodistal spine.
Pleon dextrally twisted. In males, lateral margin of third tergite with dense long setae. Male first pleopods (Fig. 2 C, D) strongly twisted; inferior lamella broad, with double row of small spines on rounded distal margin (larger distal spines strongly curved, hooked), followed by row of short stiff setae on lateral margin; internal lobe with rounded distal portion, bearing dense short to long setae on margin and inner surface; external lobe relatively slender, not reaching distal margin of inferior lamella. Second pleopod (Fig. 2 E) with basal segment naked; distal segment slightly twisted, endopod rather clearly delimited, bearing prominent tuft of stiff setae distally; appendix masculina moderately narrow, rounded terminally, with numerous marginal or submarginal setae. Third to fifth pleopods subequal in length, each with well-developed, moderately slender exopod and rudimentary endopod.
Telson (Fig. 1 F) with deep lateral indentations; median cleft relatively deep, narrow; posterior lobes strongly asymmetrical, subtriangular with rounded tips, terminal and lateral margins unarmed, each with row of long setae.
Female unknown.
Colouration in life. Shield entirely orange; calcified median part of posterior carapace orange, lateral parts whitish. Ocular peduncles orange, corneas dark gray. Antennular and antennal peduncles also orange, antennal flagellum red. Ambulatory legs with large white spots on red ground colour.
Distribution. At present known only from off Kerala coast, southwestern India; at depths of 100– 110 m.
Habitat. The three individuals all used shells of Fusinus colus (Linnaeus) (Mollusca: Gastropoda: Fasciolariidae). No association with coelenterates was seen.
Etymology. The specific epithet luculentus (= colourful) refers to the vivid living colour of the new species.
Remarks. Only three male specimens have been available for study, and they are very similar, not showing significant intraspecific variation.
As McLaughlin & Provenzano (1975) argued, Paguristes can be divided into two groups on the basis of the armature of the posterior lobes of the telson (with or without spines on the terminal margins). The diagnostic value of this character has been supported by subsequent workers (e.g., Miyake 1978; Komai 2001; McLaughlin & Rahayu 2005; Rahayu 2006; Rahayu & McLaughlin 2006; McLaughlin 2008). Paguristes luculentus n. sp. has unarmed posterior lobes of the telson, and thus is referred to the group B as defined by McLaughlin & Provenzano (1975). The new species is easily distinguished from the 27 Indo-West Pacific species referred to the group B (see Tab. 1) by the dense covering of small corneous-tipped spines on the dorsal surfaces of chela and carpi of the chelipeds and numerous tiny corneous-tipped or corneous spines, arranged in several irregular longitudinal rows, on the mesial faces of the dactyli of the second pereopods. No other species placed in the group B display such characteristics (Komai 2001, 2010; McLaughlin & Rahayu 2005; Rahayu 2006, 2007; Rahayu & McLaughlin 2006; McLaughlin 2008; Rahayu & Forest 2009). The armature of the mesial surfaces of the cheliped dactyli also appears characteristic to the new species: the mesial faces are covered with numerous scattered small spines becoming smaller and blunt ventrally, none arranged in distinct row(s).
Among the 54 Indo-West Pacific species of the genus (Tab. 1), the armature of the telson remains unknown for P. barnardi Forest, 1954, P. gamianus (H. Milne Edwards, 1836), P. incomitatus, P. macrotrichus Forest, 1954, P. mundus and P. seminudus Stimpson, 1858. Paguristes barnardi and P. gamianus are easily distinguished from P. luculentus n. sp. by the quite different armature and dense setation of the right second pereopod (cf. Forest 1954: pl. IV).
Paguristes incomitatus is readily separated from the new species by the antennular peduncles distinctly overreaching the distal corneal margins, the short antennal flagellum (shorter than the shield) and the chelae with sparse spines and dense setation on the dorsal surface (Alcock 1905). The short antennal flagellum suggests that P. incomitatus might belong to the group A, or other genus such as Areopaguristes or Pseudopaguristes, although the gill formula needs to be verified for P. incomitatus.
Species Geographicalrange Group assignment References
Paguristes acanthomerus Ortmann, 1892 Japan, Korea, Taiwan B Komai (2001); McLaughlin et al. (2007) Paguristes aciculus Grant, 1905 Australia, Indonesia A Rahayu (2006); McLaughlin (2008) Paguristes albimaculatus Komai, 2001 Japan, Taiwan, Philippines B Komai (2001); McLaughlin et al. (2007);
Rahayu & Forest (2009)
Paguristes alegrias Morgan, 1987 Northern and Western Australia A Morgan (1987b); McLaughlin (2008) Paguristes alcocki McLaughlin & Rahayu, 2005 Westrm Australia, Indonesia, Philippines B McLaughlin & Rahayu (2005); McLaughlin (2008)
Paguristes antennarius Rahayu, 2006 Madagascar, Indonesia, Taiwan A Rahayu (2006; 2007); McLaughlin et al.
(2007)
Paguristes arostratus Rahayu, 2006 Taiwan, Indonesia, Philippines B Rahayu (2006); McLaughlin et al. (2007);
Rahayu & Forest (2009)
Paguristes aulacis Rahayu & Forest, 2009 Philippines B Rahayu & Forest (2009)
Paguristes balanophilus Alcock, 1905 Gulf of Oman, Andaman Sea B Rahayu & McLaughlin (2006) Paguristes barbatus (Heller, 1862) New Zealand A Forest & McLaughlin (2000) Paguristes barnardi Forest, 1954 South Africa unknown Forest (1954)
Paguristes brachyrostris Rahayu, 2006 Indonesia, Philippines B Rahayu (2006); Rahayu & Forest (2009) Paguristes brevirostris Baker, 1905 Southeastern Australia A McLaughlin (2008)
Paguristes calvus Alcock, 1905 Red Sea, Bay of Bengal, Andaman Sea, Philippines, B Rahayu & McLaughlin (2006);
Taiwan McLaughlin et al. (2007); Rahayu & Forest (2009)
Paguristes ciliatus Heller, 1862 Nicobar Islands, eastern Indian Ocean A McLaughlin & Dworschak (2001) Paguristes crinitimanus McLaughlin, 2008 Queensland, Australia B McLaughlin (2008)
Paguristes dampierensis McLaughlin, 2008 Western Australia A McLaughlin (2008)
Paguristes digitalis Stimpson, 1858 Japan, Korea, Far Eastern Russia A Komai (2001)
……continued on the next page Species Geographicalrange Group assignment References
Paguristes doederleini Komai, 2001 Japan, Taiwan A Komai (2001); McLaughlin et al. (2007) Paguristes frontalis (H. Milne Edwards, 1836) South and Western Australia B McLaughlin (2008)
Paguristes gamianus (H. Milne Edwards, 1836) South Africa unknown Forest (1954)
Paguristes geminatus McLaughlin, 2008 Queensland, Australia A McLaughlin (2008)
Paguristes gonagrus (H. Milne Edwards, 1836) Japan to Philippines B Rahayu & Forest (1999); Komai (2010) Paguristes incomitatus Alcock, 1905 Gulf of Aden, Maldives, India, Sri Lanka unknown Alcock (1905); Thomas (1989) Paguristes jalur Morgan, 1992 Cocos (Keeling) Islands, Christmas Islands, Japan, B Morgan (1992); Osawa & Takeda (2004);
Mariana Islands McLaughlin (2008)
Paguristes jousseaumei Bouvier, 1892 Red Sea A Dechancé (1963)
Paguristes kimberleyensis Morgan & Forest, 1991 Western Australia B Morgan & Forest (1991); McLaughlin
(2008)
Paguristes lauriei McLaughlin & Hogarth, 1998 Seychelles, Réunion B McLaughlin & Hogarth (1996); Rahayu
(2007)
Paguristes lewinsohni McLaughlin & Rahayu, 2005 Red Sea to Arabian coast, Philippines B McLaughlin & Rahayu (2005); Rahayu &
Forest (2009)
Paguristes longirostris Dana, 1851 India, Andaman Sea, Singapore A Alcock (1905); McLaughlin (2002) Paguristes longisetosus Morgan, 1987 Tasmania, South and Western Australia A Morgan (1987a); McLaughlin (2008) Paguristes macrops Rahayu & Forest, 2009 Philippines, Japan B Rahayu & Forest (2009); Osawa &
Rahayu (2012)
Paguristes macrotrichus Forest, 1954 South Africa unknown Forest (1954)
Paguristes miyakei Forest & McLaughlin, 1998 Western Australia, Japan, Taiwan A Forest & McLaughlin (1998); McLaughlin
et al. (2007); McLaughlin (2008) Paguristes mundus Alcock, 1905 Andamans, eastern Indian Ocean unknown Alcock (1905)
Paguristes ocellus Komai, 2010 Japan B Komai (2010)
Paguristes ortmanni Miyake, 1978 Japan, Korea, Far East Russia A Komai (2001)
……continued on the next page Species Geographicalrange Group assignment References
Paguristes palythophilus Ortmann, 1892 Madagascar to Japan B Komai (2001); McLaughlin et al. (2007); McLaughlin (2008); Rahayu & Forest (2009)
Paguristes petalodactylus Rahayu, 2007 Madagascar B Rahayu (2007)
Paguristes pugil McCulloch, 1913 Southeastern Australia A McLaughlin (2008) Paguristes puniceus Henderson, 1896 Madagascar, Bay of Bengal, Andaman Sea, A McLaughlin (2004; 2008); McLaughlin et
Indonesia, Australia, Taiwan al. (2007); Rahayu (2007)
Paguristes purpureantennatus Morgan, 1987 Western Australia B Morgan (1987b); McLaughlin (2008) Paguristes pusillus Henderson, 1896 Off Sri Lanka B McLaughlin & Rahayu (2005) Paguristes runyanae Haig & Ball, 1988 Indonesia, Philippines B Haig & Ball (1988); Rahayu & Forest
(2009)
Paguristes seminudus Stimpson, 1858 Japan unknown Stimpson (1858, 1907) Paguristes simplex Rahayu & McLaughlin, 2006 Madagascar, Western Australia B Rahayu & McLaughlin (2006); McLaughlin (2008)
Paguristes sinensis Tung & Wang, 1966 China A Tung & Wang (1966); Komai (2009) Paguristes squamosus McCulloch, 1913 New South Wales, Australia A McLaughlin (2008) Paguristes subpilosus Henderson, 1888 New Zealand A Forest & McLaughlin (2000) Paguristes sulcatus Baker, 1905 Southern Australia A McLaughlin (2008) Paguristes tosaensis Komai, 2010 Japan B Komai (2010)
Paguristes triton McLaughlin, 2008 Northwestern Australia B McLaughlin (2008) Paguristes versus Komai, 2001 Japan, Taiwan, Philippines B Komai (2001); McLaughlin et al. (2007);
Rahayu & Forest (2009)
Paguristes zhejiangensis Wang & Tung, 1982 East China Sea B Wang & Tung (1982); McLaughlin et al.
(2010)
Paguristes macrotrichus differs from P. l u c ul en t us n. sp. in the short rostrum only exceeding as far as the lateral projections and the dactylus of the second pereopod being devoid of small spines on the mesial face and bearing fewer (apparently less than 15) and longer corneous spines on the ventral margin (Forest 1954).
Paguristes mundus is superficially similar to P. luculentus n. sp. in the long antennal flagellum and the general armature of the chelipeds (cf. Alcock 1905: pl. III, fig. 5), but differs in the short, broadly triangular rostrum, multidenticulate ocular acicles, the left cheliped being smaller than the right cheliped, and the presence of a row of fine setae on the ventral margins of ambulatory dactyli.
The specific identity of P. seminudus is obscure. The type material of Stimpson’s (1958) taxon is no longer extant (Evans 1967; Manning & Reed 2006), and it is difficult to establish its taxonomic identity without examination of topotypic specimens that match the descriptions by Stimpson (1858, 1907). Nevertheless, the description by Stimpson (1907) provides some characters that distinguish our new taxon from P. seminudus: “Eyes very stout for the genus, but long, considerably longer than the front is wide, and much overreaching the peduncle of the antennulae”; “Antennae shorter than carapax”; Cheliped “carpus and hand densely hairy and spinulose”; “Color olive or brownish; antennae annulated; maxillipeds spotted with white; tips of all the feet white”. As discussed by McLaughlin (2008), identifications of P. seminudus by subsequent authors (Miyake 1978; Miyake & Imafuku 1980; Baba 1986; McLaughlin et al. 2007) are not correct. Specimens referred to P. seminudus by these authors most probably represent P. zejiangensis Wang & Tung, 1982 (Komai, unpublished data).
As mentioned above, eight species of Paguristes have been recorded from Indian waters, and thus the new species is the ninth of the genus to be recorded from the area.
description: Published as part of Komai, Tomoyuki, Reshmi, Rema & Kumar, Appukuttannair Biju, 2015, A new species of the hermit crab genus Paguristes Dana, 1851 (Crustacea: Decapoda: Anomura: Diogenidae) from southwestern India, pp. 517-532 in Zootaxa 3937 (3) on pages 518-530, DOI: 10.11646/zootaxa.3937.3.5, http://zenodo.org/record/232472