Petrarctus jeppiaari, Chan, 2017

Chan, Tin-Yam, 2017, A new slipper lobster of the genus Petrarctus Holthuis, 2002 (Crustacea, Decapoda, Scyllaridae) from Southwest coast of India, Zootaxa 4329 (5), pp. 477-486 : 478-484

Petrarctus jeppiaari sp. nov.

( Figs. 1 ; 2; 3A, C, E; 4A, C, E)

Type material. HOlOtype: India, Jeppiaar fishing harbOr, MuttOm , Tamil Nadu, cOmmercial trawler, 18 Mar 2017, OVigerOus female 24.6 mm cl (ZSI/ WGRC /IR-INV) . Paratypes: India, Jeppiaar fishing harbOr, MuttOm , Tamil Nadu, cOmmercial trawler, 21 Mar 2017, 1 male 24.3 mm cl, 4 OVigerOus females 22.8–26.2 mm cl, 5 females 14.5–19.2 mm cl (DABFUK/AR-ACH-1-10), 4 males 19.4–25.4 mm cl, 2 OVigerOus females 21.4 and 26.2 mm cl, 1 female 24.2 mm cl (DABFUK), 2 males 17.7–19.4 mm cl, 4 OVigerOus females 19.0– 25.5 mm cl, 1 female 21.0 mm cl (DABFUK).

Description. BOdy irregularly rugOse and nOdulOse, almOst entirely cOVered with tubercles. ROstrum distinct and as a sharp tubercle. Pregastric tOOth absent, replaced by grOup Of tubercles. AnteriOr submedian ridge ending in large tubercle ( Fig. 2A ). Gastric tOOth high and Obtuse triangular ( Fig. 3C ), surface cOVered with flatten tubercles, pOsteriOr part accOmpanied with a curVed rOw Of 3 Or 4 tubercles alOng twO sides ( Fig. 2A ). Cardiac tOOth highly eleVated, larger than gastric tOOth and abOut 1.5 times higher than latter, tip blunt, pOsteriOr margin cOVered with 2 rOws Of 5 Or 6 tubercles that becOming mOre distinct pOsteriOrly, anteriOr part accOmpanied with rOw Of 2 large tubercles On each side. POsteriOr submedian ridge cOmpOsed Of 3 Or 4 tubercles in shOrt curVe rOw. AnteriOr and pOsteriOr branchial carinae separated widely by cerVical grOOVe and with 1 distinct tubercle in-between; anteriOr branchial carina terminating anteriOrly intO 2 sharp tubercles; tip Of pOsteriOr branchial carina as a distinct tOOth and fOllOwed by twO rOws Of 7 Or 8 distinct tubercles. ROw Of 2 Or 3 indistinct tubercles that sOmetimes fused intO carina present between pregastric tOOth and anteriOr branchial carina. 4 large intermediate tubercles present. Oblique rOw Of 2 sharp tubercles present between intermediate tubercles and pOsteriOr branchial carina. 2 Or 3 indistinct tubercles alsO present between intermediate tubercles and pOsteriOr submedian ridge. Lateral margin Of carapace with 4 Or 5 anterOlateral, 3 Or 4 mediOlateral and dOuble rOws Of 7 Or 8 pOsterOlateral teeth. 3 Or 4 larger tubercles present between pOsterOlateral margin and pOsteriOr branchial carina. POstOrbital carina with distinct tubercle. IntercerVical carina cOmpOsed Of 11 Or 12 tubercles. Marginal grOOVe alOng pOsteriOr margin Of carapace wide and mOderately deep; anteriOr margin as transVerse rOw Of distinct but unequal tubercles, with 2 submedian tubercles largest; pOsteriOr margin distinctly incised medially, densely cOVered with highly eleVated rOund tubercles that smaller than thOse On anteriOr margin ( Fig. 2A ).

AnteriOr part Of thOracic sternum with anteriOr margin deeply U-shaped and bearing distinct medial incisiOn; medially brOadly sunken and sOmetimes with 1–3 indistinct median tubercles behind medial incisiOn; lateral bOrder sharply ridged and fOrming large tOOth anteriOrly. ThOracic sternites II–V each bearing median tubercle, weaker in females, that On sternite II sOmetimes eVen indistinct ( Fig. 3E ).

AbdOmen with tergite I bearing sOme indistinct lOngitudinal shOrt carinae at median part, laterally cOVered with 3 Or 4 tubercles ( Fig. 4A ). Articulated parts Of tergites II–V smOOth and with pOsteriOr margins crenulated. NOn-articulated parts Of tergites II–V each with wide transVerse grOOVe and well-deVelOped median carina; median carina highly eleVated and hump like On tergites II–IV, hump lOwer On tergite II and that On tergite III Only slightly higher than that Of tergite IV ( Fig. 4C ); bOth sides Of transVerse grOOVe entirely cOVered with large tubercles that extending OntO pleura ( Fig. 4C ). POsteriOr margins Of tergites I and II distinctly incised medially while thOse Of tergites III tO V prOtruding medially as OVerhanging lObes. POsteriOr margin Of tergite VI distinctly serrated; with 3 large tubercles haVing 4 smaller but distinct tubercles in-between ( Fig. 4E ). PleurOn I shOrt; pleura II–V brOad and bearing tuberculated median carina as well as many distinct tubercles at pOsteriOr part, pOsteriOr margins crenulated. AnteriOr calcified part Of telsOn with 2 pairs Of tubercles.

Antennal segment VI with anteriOr margin cut intO 6 lOng Obtuse teeth and 1 inner shOrt tOOth. Antennal segment IV with anteriOr margin haVing 6 Or 7 shOrt teeth, inner secOnd One largest; Outer margin with 3 Or mOre Often 4 larger teeth; dOrsal surface with strOng Oblique median carina, additiOnal weak carina cOmpOsed Of indistinct tubercles alsO present near Outer margin Of segment ( Fig. 3A ).

PereiOpOd I shOrt and rObust, with dactylus glabrOus ( Fig. 2B ). Dactylus Of pereiOpOd II lOngest in all pereiOpOds ( Fig. 2C ), thOse Of pereiOpOds III and IV bearing shOrt pubescence On dOrsal surface. BOth dOrsal and Ventral margins On prOpOdi and meri Of pereiOpOds III and IV cOVered with lOng hairs, dense On pereiOpOd III ( Fig. 2D ) but fewer On pereiOpOd IV ( Fig. 2E ). PrOpOdus and carpus Of pereiOpOd V naked On dOrsal surface ( Fig. 2F ).

Eggs small and numerOus, abOut 0.3–0.4 mm in diameter (nOt eyed).

Coloration. BOdy including pereiOpOds generally brOwnish and mOttled with white Or yellOwish Orange markings, Ventral surface mOstly whitish. Eyes dark brOwn. Articulated part Of abdOminal tergite I yellOwish Orange and sOmewhat mOttled with Orange markings, median part with thin bright blue transVerse stripe alOng anteriOr margin fOllOwing by an inVerted triangular dark brOwn marking extending OntO nOn-articulated part ( Figs. 1 , 4A ). AbdOminal sOmite V tO tail-fan mOstly whitish. Eggs yellOwish Orange.

Distribution. At present knOwn Only frOm Off MuttOm, sOuthwestern cOast Of India, at depths Of abOut 150– 200 m.

Etymology. The species is named after the fishing harbOr where this new species was discOVered. Jeppiaar alsO stands fOr Jesuadimai Pangu Raj, whO was a fisherman Of MuttOm whO became a pOlitician making great cOntributiOns tO the lOcal cOmmunities and he is the FOunder and ChancellOr Of the Sathyabama UniVersity, Chennai, India.

Remarks. The present slipper lObster was Only discOVered in the bycatch Of trawlers Operating frOm Jeppiaar fishing harbOr in MuttOm, sOuthwest cOast Of India at depths Of 150– 200 m. HOweVer, this species has nOt yet been fOund in the Other nearby deep-sea fishing pOrts alOng the east cOast Of India, such as TuticOrin, nOr alOng the west cOast such as Neendakara and Sakthikulangara. MOrphOlOgically, this species clOsely resembles P. veliger in haVing a Very high cardiac tOOth and the abdOminal sOmites III and IV with dOrsal humps Of similar height (see Yang et al. 2008). HOweVer, its cOlOratiOn is different frOm P. veliger in that the articulated part Of the abdOminal tergite I lacks a large dark circular median spOt ( Fig. 4B ; Yang et al. 2014: fig. 6D, alsO see HOlthuis 2002). Instead, the articulated part Of the abdOminal tergite I in this species bears a thin bright blue stripe ( Figs. 1 , 4A ) sOmewhat similar tO P. rugosus (H. Milne Edwards, 1837) and P. brevicornis ( HOlthuis, 1946) (see Chan & Yu 1986, 1993; HOlthuis 2002). It shOuld be pOinted Out that all the preserVed specimens Of P. veliger examined in the present study bear a dark circular spOt On the abdOminal tergite I althOugh HOlthuis (2002) mentiOned that the hOlOtype, which was preserVed since 1963 lOst all its cOlOratiOn. The bright blue stripe On the abdOminal tergite I in this Indian fOrm faded quickly after preserVatiOn like in P. rugosus and P. brevicornis , with Only the dark cOlOred inVerted triangular spOt behind still remaining.

AlthOugh the type lOcality Of P. veliger is in the Andaman Sea near India, a cOmparisOn Of P. jeppiaari sp. nov. with tOpOtypic material, paratypes and additiOnal P. veliger specimens frOm the Philippines and Taiwan (see HOlthuis 2002; Yang et al. 2014) reVealed seVeral mOrphOlOgical differences between the present Indian species and P. veliger . The mOst ObViOus differences are the height Of the cardiac tOOth, shape Of the anteriOr part Of the thOracic sternum and the deVelOpment Of abdOminal sculpture. The cardiac tOOth in the P. jeppiaari sp. nov. is generally blunt and Only slightly (abOut 1.5 times) higher than the gastric tOOth ( Fig. 3C ). In P. veliger , hOweVer, the cardiac tOOth is generally sharp and much (abOut 2 times) higher than the gastric tOOth ( Fig. 3D , alsO see HOlthuis 2002: figs. 15B, 16B). The anteriOr part Of the thOracic sternum has the lateral ridges sharp in the P. jeppiaari sp. nov. ( Fig. 3E ) but flat and bearing a lOngitudinal furrOw (sOmetimes rather shallOw) in P. veliger ( Fig. 3F ). MOreOVer, there is Often a distinct median lOngitudinal carina present On the anteriOr part Of the thOracic sternum in P. veliger ( Fig. 3F ) but such a carina is represented by 1–3 tubercles in the P. jeppiaari sp. nov. ( Fig. 3E ). The abdOmen is entirely cOVered with well-deVelOped tubercles ( Fig. 4C ) and haVing the pOsteriOr margin Of tergite VI distinctly serrated ( Fig. 4E ) in P. jeppiaari sp. nov. In P. veliger , the tubercles behind the transVerse furrOw On each abdOminal sOmite are much less deVelOped than the tubercles befOre the transVerse furrOw and sOmetimes eVen indistinct fOr thOse at pOsteriOr sOmites ( Fig. 4D ; HOlthuis 2002: figs 15, 16). FurthermOre, the pOsteriOr margin Of the abdOminal tergite VI Only bears three large tubercles and withOut smaller tubercles in-between ( Fig. 4F ; HOlthuis 2002: fig. 15A).

Further minOr differences are alsO ObserVed between P. jeppiaari sp. nov. and P. veliger . The rOund tubercles On the pOsteriOr bOrder Of the carapace are denser and mOre eleVated in P. jeppiaari sp. nov. ( Fig. 4A ) than in P. veliger ( Fig. 4B ). The teeth at the anteriOr margin Of antennal segment VI are Obtuse in P. jeppiaari sp. nov. ( Fig. 3A ) but narrOwer and sharper in P. veliger ( Fig. 3B ). The Outer margin Of antennal segment IV bears 3, Or mOre Often 4, larger teeth (fOurth tOOth if present always large) in P. jeppiaari sp. nov. ( Fig. 3A ), but Only 3 large teeth and an indistinct pOsteriOr tOOth in P. veliger ( Fig. 3B ; HOlthuis 2002: figs. 15A, 16A).

AlthOugh mOlecular genetic analysis Of the barcOding gene COI shOws that the Indian species is sister tO P. veliger ( Fig. 5A ), the twO exhibit a high nucleOtide diVergence Of 8.2–9.7%, which is generally cOrrespOnds tO species-leVel differences in Other decapOd crustaceans ( Chan et al. 2009; Malay & Paulay 2009; Lai et al. 2010). At this juncture, it is alsO impOrtant tO treat the taxOnOmy Of P. rugosus (H. Milne Edwards, 1837) , the type species Of Petrarctus HOlthuis, 2002 . This species was described frOm POndicherry in sOutheastern India (H. Milne Edwards 1837), a site nOt far frOm MuttOm at the sOuthwestern tip Of India where P. jeppiaari sp. nov. was discOVered. The exact identity Of P. rugosus is prOblematic because the Original descriptiOn was relatiVely brief, nO figures were eVer prOVided and the type is lOst (see HOlthuis 1991). AdditiOnal searches in the Muséum natiOnal d’HistOire naturelle, Paris by One Of the authOrs (TYC) alsO failed tO find the material. HOlthuis (1946, 1991, 2002) was cOnfident Of the identity Of the species, haVing examined material identified tO this species frOm VariOus IndO-West Pacific lOcalities (but withOut specimen frOm India), and he treated Arctus tuberculatus Bate, 1888 , as a juniOr subjectiVe synOnym Of P. rugosus . HOlthuis (1946) argued that Scyllarus rugosus H. Milne Edwards, 1837 belOngs tO Petrarctus by the abdOmen differing frOm mOst Scyllarus sensu latO Fabricius, 1775 in haVing deep transVerse furrOws and Obtuse median carina as H. Milne Edwards (1837: 283) stated that the: “AbdOmen prOfOndément sillOnné en traVers, et surmOnté d’une créte médiane Obtuse, qui fOrme sur le trOisiéme anneau une gibbOsité trèsmarquée.” Species Of Bathyarctus HOlthuis, 2002 , hOweVer, alsO haVe these characters althOugh the median carina Of abdOminal sOmite III is lOwer than that Of sOmite IV ( HOlthuis 2002); and H. Milne Edwards (1837) neVer described the cOnditiOn Of the median carinal armature On abdOminal sOmite IV—Only that the median carina On sOmite III was strOngly deVelOped. Bathyarctus has a differently structured anteriOr margin Of thOracic sternum frOm Petrarctus , but this character was nOt mentiOned by H. Milne Edwards (1837). Within Petrarctus , the Original descriptiOn Of P. rugosus (H. Milne Edwards 1837: 283) alsO stated that there are fOur teeth On the Outer margin Of the antennal segment IV: “Quatre dents sur le bOrd externe du pénultième article des antennes externes (celle qui Occupe l’angle antérieur nOn cOmprise).” This differentiates it frOm P. demani ( HOlthuis, 1946) and P. brevicornis but is a character still shared with P. tuberculatus , P. holthuisi Yang, Chen & Chan, 2008 , P. veliger and P. jeppiaari sp. nov. (as well as in sOme species Of Bathyarctus ). The median hump On abdOminal sOmite III is nOt particularly higher than that Of the abdOminal sOmite IV in bOth P. veliger and P. jeppiaari sp. nov., and therefOre, highly likely that the present fOrm dOes nOt belOng tO H. Milne Edwards’ (1837) species which appears tO haVe the median hump at the abdOminal sOmite III mOst prOminent. AlthOugh P. rugosus has an Indian type lOcality, there are nO illustrated Or detailed taxOnOmic repOrts On any Indian material Of this species, except fOr its suppOsed larVae ( Kumar et al.

2009). NeVertheless, the COI sequence ( JQ229889 ) Of a P. rugosus specimen frOm Chennai ( Jeena et al. 2016, whO alsO mentiOned that the species is cOmmOn there) Off the eastern cOast Of India and near tO POndicherry, matches well (98.5–98.8% sequence similarity) with material frOm Taiwan and IndOnesia currently assigned tO P. rugosus ( Fig. 5 ).

AlthOugh HOlthuis (1946, 1991, 2002) was cOnfident abOut identifying his material frOm Indian and Pacific Oceans with H. Milne Edwards’ (1837) specimen Of P. rugosus , we are less certain. As discussed earlier, there are nOw six species in Petrarctus and anOther six species in Bathyarctus , and sOme Of them are separated frOm P. rugosus sensu strictO by characters that were nOt characterized by H. Milne Edwards (1837; like the relatiVe height Of the median carina On abdOminal sOmite IV); and the shape Of the anteriOr margin Of the thOracic sternum is nOt knOwn (sO it may eVen be a species Of Bathyarctus ). TO stabilize the taxOnOmy Of Petrarctus HOlthuis, 2002 , and tO ensure that the identity Of the type species remains as defined by HOlthuis (1946, 1991, 2002), we here designate a female specimen (19.9 mm cl) (CASAU) recently cOllected frOm Pazhayar fishing pOrt, 11°21’30.28”N, 79°49’39.83”E, Tamil Nadu On 15 Jul 2017, as the neOtype Of Scyllarus rugosus H. Milne Edwards, 1837 . This lOcatiOn is just sOuth Of the Original type lOcality in POndicherry, and the specimen fits well the current mOrphOlOgical cOncept Of P. rugosus , has a cOlOr pattern ( Fig. 5B ) that agrees with what is nOw recOgnized fOr the species and has 99.2% sequence similarity ( MF669474 ) tO the Chennai material ( Fig. 5A ).

Figures

FIGURE 1. Petrarctus jeppiaari sp. nov., Jeppiaar fishing harbor, Muttom, southwestern India, ovigerous female holotype 24.6 mm cl (ZSI / WGRC / IR-INV).

FIGURE 2. Petrarctus jeppiaari sp. nov., Jeppiaar fishing harbor, Muttom, southwestern India, ovigerous female holotype 24.6 mm cl (ZSI / WGRC / IR-INV): A, carapace, dorsal view; B, pereiopod I; C, pereiopod II; D, pereiopod III; E, pereiopod IV; F, pereiopod V. All right pereiopods. Scales = 5 mm.

FIGURE 3. A, C, E, Petrarctus jeppiaari sp. nov., Jeppiaar fishing harbor, Muttom, southwestern India, ovigerous female holotype 24.6 mm cl (ZSI / WGRC / IR-INV); B, D, F, P. veliger Holthuis, 2002, Phuket, Thailand, female 27.5 mm cl (ZRC 2000.0851). A – B, right antenna, dorsal view; C – D, dorsal carapace, lateral view; E – F, thoracic sternum, ventral view. Scales = 5 mm.

FIGURE 4. A, C, E, Petrarctus jeppiaari sp. nov., Jeppiaar fishing harbor, Muttom, southwestern India, ovigerous female holotype 24.6 mm cl (ZSI / WGRC / IR-INV); B, D, F, P. veliger Holthuis, 2002, Phuket, Thailand, female 27.5 mm cl (ZRC 2000.0851). A – B, abdominal tergite I, dorsal view, sparser dots representing bright blue markings, denser dots representing darker markings; C – D, abdominal tergite II – IV, lateral view; E – F, abdominal tergite VI, dorsal view. Scales = 5 mm.

FIGURE 5. A, Bayesian tree based on partial sequences of the mitochondrial COI gene (657 bps) of Petrarctus species and outgroup. Numbers at nodes are posterior probabilities from Bayesian inference analysis. Only values> 0.8 are shown; B, Petractus rugosus (H. Milne Edwards, 1837), Pazhayar fishing port, Tamil Nadu, southeastern India, female neotype 19.9 mm cl (CASAU).