Ciliopagurus grandis, Komai, Tomoyuki, Reshmi, Rema & Kumar, Appukuttan Nair Biju, 2012

Komai, Tomoyuki, Reshmi, Rema & Kumar, Appukuttan Nair Biju, 2012, A new species of the hermit crab genus Ciliopagurus Forest (Crustacea: Decapoda: Anomura: Diogenidae) from southern India, Zootaxa 3266, pp. 53-61 : 53-61

publication ID	https://doi.org/ 10.5281/zenodo.280763
DOI	https://doi.org/10.5281/zenodo.6176578
persistent identifier	https://treatment.plazi.org/id/03DDA531-FFD3-FF9B-D19E-CE1FFA88FD44
treatment provided by	Plazi
scientific name	Ciliopagurus grandis
status	sp. nov.

Treatment

Ciliopagurus grandis View in CoL n. sp.

( Figs 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 )

Material examined. Holotype: male (sl 13.7 mm), off Sakthikulangara, Kerala State, India, depths 10–15 m, 24–29 January 2011, CBM-ZC 10663.

Paratypes: 2 males (sl 9.6, 12.8 mm), 1 female (sl 10.0 mm), same data as holotype, CBM-ZC 10664; 2 males (sl 17.1, 14.0 mm), 1 female (sl 9.8 mm), off Sakthikulangara, Kerala State, India, depths 10–15 m, 24–29 January 2011, Museum of the Department of Aquatic Biology and Fisheries, University of Kerala, AR AN 14–16.

Description. Cephalothorax ( Fig. 1 View FIGURE 1 A, B) fairly depressed dorsoventrally. Shield ( Fig. 2 View FIGURE 2 A) about 1.1 times longer than broad; anterolateral margins sloping; anterior margin between rostrum and lateral projections very slightly concave; posterior margin roundly truncate; dorsal surface flat, with scattered shallow pits anterolaterally and few tufts of stiff setae laterally; Y-shaped decalcified suture present posteriorly. Rostrum obtuse, rounded, slightly exceeding lateral projections. Lateral projections also obtuse, unarmed.

Ocular peduncles ( Fig. 2 View FIGURE 2 A) equal in length, long and slender, 0.8 times as long as shield and 7.0–7.5 times longer than corneal width, cylindrical, slightly inflated basally and not dilated in corneal region; dorsal surfaces with scattered very short setae. Ocular acicles narrowly triangular, mesial margins nearly straight, lateral margins sloping, terminating in small marginal spine; narrowly separated basally (distance between acicles less than half width of 1 acicle).

Antennal peduncle ( Fig. 2 View FIGURE 2 A) moderately long. Ultimate segment reaching corneal bases, 0.4–0.5 times as long as shield and about twice length of penultimate segment, dorsally with scattered minute setae. Penultimate segment with several short to moderately short setae. Basal segment short; ventrodistal margin produced in triangular process; laterodistal margin denticulate; lateral surface unarmed or armed with minute spinule dorsally.

Antennal peduncles ( Fig. 2 View FIGURE 2 A) reaching distal one-fourth to one-fifth of ocular peduncles. Fifth segment slightly flattened dorsoventrally, with scattered tufts of very short setae. Fourth segment unarmed or armed with minute spine dorsodistally, with short setae. Third segment with small spine at ventrodistal angle and some tufts of setae. Second segment with dorsolateral distal angle produced, terminating in simple or bifid spine, lateral margin unarmed; dorsomesial distal angle with minute spinule, mesial margin with stiff setae. First segment almost concealed by anterolateral margin of branchiostegite; ventrodistal margin with 1 minute spine lateral to antennal gland opening. Antennal acicle ( Fig. 2 View FIGURE 2 B) reaching proximal two-fifths of ocular peduncle, terminating in acute, simple or bifid spine; mesial margin with 1 or 2 tiny spines or spinules, lateral margin unarmed or 1 tiny spine. Flagellum slightly overreaching chelipeds; each article with some minute setae (<half length of one article) on distal margin.

Mandible (not illustrated) without distinguishing characters. Maxillule with endopod bearing 7 bristles on moderately well-developed internal lobe, external lobe well-developed, slender, recurved ( Fig. 2 View FIGURE 2 C). Maxilla ( Fig. 3 View FIGURE 3 A) with basally broad, tapering endopod reaching scaphognathite in distal extension. First maxilliped ( Fig. 3 View FIGURE 3 B) with basal segment of exopod broad. Second maxilliped ( Fig. 3 View FIGURE 3 C) with basis-ischium fusion incomplete; exopod about twice of endopod in length, moderately broad. Third maxilliped ( Fig. 2 View FIGURE 2 D) with basis and ischium separated; basis with 2 tiny corneous-tipped denticles; ischium with crista dentata well-developed, without accessory tooth ( Fig. 2 View FIGURE 2 E); merus and carpus unarmed on dorsodistal margins; exopod broad (broadest at proximal one-third), uncalcified in lateral half ( Fig. 2 View FIGURE 2 F).

Chelipeds slightly unequal, short, left larger ( Fig. 1 View FIGURE 1 A). Left cheliped ( Fig. 4 View FIGURE 4 A–C) with dactylus subequal in length to palm; cutting edge with 1–3 prominent calcareous teeth proximally, terminating in very strong, black corneous claw; dorsomesial margin not markedly delimited, dorsal and mesial surface with 5 irregular, shallow, transverse furrows and irregular rows of small, corneous-tipped spines or transverse rows of corneous-tipped rods forming stridulating apparatus (stridulating rods restricted to mesial surface), these armature partially obscured by stiff setae; ventral surface with several tufts of stiff setae. Palm slightly longer than carpus; dorsolateral or lateral margin not delimited, dorsal, lateral and mesial surfaces each marked by shallow transverse furrows, each furrow on dorsal and lateral surfaces bounded proximally by low, setose, microscopically denticulate ridge ( Fig. 4 View FIGURE 4 D) (main ridges 6–9 in number on dorsal surfaces, some of them interrupted; some interspersing striae also present); fixed finger distally with scattered corneous-tipped spines interspersed with stiff setae and proximally with short transverse ridges bearing corneous spinules; furrows of mesial surface bounded proximally by transverse rows of corneous-tipped rods forming stridulating apparatus (for details, see below); ventral surface laterally with 4 or 5 transverse ridges consisting of small corneous tubercles and mesially with 4 transverse striae, and with short to long setae on ridges and striae. Carpus 0.6–0.7 times as long as merus, subtriangular; dorsal, lateral and mesial surfaces each shallow transverse furrows, and each furrow bounded proximally by low, microscopically denticulate or smooth ridges (5 or 6 main ridges present; corneous-tipped spines conspicuous on dorsal surface); distal margin microscopically denticulate dorsally and laterally; dorsodistal margin with small corneous-tipped spine. Merus subtriangular; dorsal margins, lateral and to lesser extent mesial surfaces each with shallow transverse furrows, bounded proximally by low, microscopically denticulate or smooth ridges, each ridge dense short setae marginally; dorsal margin broadly arcuate, without conspicuous spines, dorsodistal margin with 2–4 small spines; mesial surface also with 1 small tubercle proximoventrally, ventromesial margin with 0–4 small tubercles; ventral surface with 1 distinct subdistal transverse ridge and some short transverse striae, lacking conspicuous spine. Ischium with ventromesial margin smooth to minutely denticulate.

Right cheliped similar to left cheliped in armature and ornamentation.

Stridulating apparatus consisting of 4 main ridges extending to ventral half of mesial surface (occasionally interrupted) and interspersing 4 or 5 short dorsal ridges or elevations bearing longitudinal corneous rods (most rods each terminating distally in small spine) ( Fig. 4 View FIGURE 4 C). Distalmost ridge bearing about 20 corneous rods decreasing in length ventrally ( Fig. 4 View FIGURE 4 E). In total, about 50–60 corneous rods present.

Ambulatory legs ( Fig. 5 View FIGURE 5 A, B, D, F) moderately long, second overreaching tips of chelipeds by 0.5–0.7 lengths of dactyli; generally similar in armature and ornamentation. Dactyli 1.1–1.3 times longer than propodi, terminating in strong terminal claws, in lateral view gently curved ventrally, in dorsal view nearly straight; dorsal surfaces each with low transverse ridges, showing as arcuate or squamiform ridges on dorsal halves of lateral and mesial surfaces, and stiff short to long setae arising from these ridges; lateral and mesial surfaces each with row of arcuate or squamiform ridges on ventral half and tufts of stiff setae; ventral surfaces with row of 15–20 slender corneous spines increasing in size distally (cf. Fig. 5 View FIGURE 5 B). Propodi each with series of prominent ridges and rows of short fine stiff setae circumscribing segment (6 main ridges and a few interspersed, short, occasionally interrupted ridges); dorsal and ventral surfaces each with additional tufts of long stiff setae. Carpi each with corneous-tipped dorsodistal spine; dorsal and lateral, and to lesser extent, mesial surfaces each with series of transverse ridges and rows of short fine setae; dorsal ridges with 1–3 minute to tiny corneous-tipped spines in second, unarmed in third. Meri with dorsal surfaces each having row of low transverse ridges extending laterally and mesially, all ridges interrupted, bearing fine short setae; dorsal surface also with sparse long setae proximally; ventral surfaces each with spinulose ridges (second) or almost smooth ridges (third) and additional tufts of long stiff setae, ventrolateral distal margin with small distal spine in second, unarmed in third. Ischium with ventral margin bearing row of minute spinules (second) or unarmed (third).

Fourth pereopods ( Fig. 2 View FIGURE 2 G) semichelate; dactylus distinctly longer than palm, somewhat curved distally, overreaching tip of fixed finger by 0.2 length, terminating in small corneous claw, lateral surface with row of corneous spines ventrally; preungual process absent. Propodal rasp very well developed, encompassing half to twothirds of lateral surface, consisting of small to elongate scales increasing in size distally. Carpus with or without dorsodistal spine. Tufts of stiff long setae present on dorsal surfaces of dactylus to merus and ventral surfaces of merus.

Fifth pereopods chelate.

Anterior lobe of sixth thoracic sternite (of third pereopods) ( Fig. 2 View FIGURE 2 H) broadly subsemicircular. Eighth thoracic sternite (of fifth pereopods) with shallow groove anteriorly.

Males with 4 unpaired left pleopods (second to fifth pleopods; length: fifth = fourth> third> second); each exopod well developed, while endopods greatly reduced, 0.2–0.3 length of exopods. Female with 4 biramous unpaired pleopods, with both rami multi-segmented and well developed.

Uropods asymmetrical. Sixth pleonal tergite ( Fig. 2 View FIGURE 2 I) about 1.5 times longer than broad, divided into two parts by distinct transverse groove across at posterior two-thirds; lateral indentations deep, narrow; posterior part with shallow median groove, posterolateral margins unarmed. Telson ( Fig. 2 View FIGURE 2 J) with posterior lobes broadly and roundly subtriangular, greatly unequal (left much larger than right), with narrow, deep median cleft; terminal margins unarmed, but with row of moderately long stiff setae.

Coloration in formalin. ( Fig. 1 View FIGURE 1 A, B). Shield orange, anterior margin whitish. Posterior carapace pale orange; branchiostegite and ventrolateral portion of posterior carapace crimson. Ocular peduncle white on dorsal face, otherwise red. Antennular and antennal peduncles whitish, antennal flagellum uniformly pale orange. Chelipeds and ambulatory legs generally orange, transverse ridges lined by red. Pleon generally white, without markings; sixth somite, telson and uropods orange. Claws of chelipeds and ambulatory legs and corneous spinules on ambulatory dactyli black or dark brown. See Fig. 1 View FIGURE 1 A, B.

Housing. Using gastropod shells, e.g., Xenophora solaris (Linnaeus, 1767) (Discopoda: Xenophoridae ), Ficus gracilis (Sowerby, 1825) and F. ficoides (Lamarck, 1822) (Discopoda: Ficidae ).

Distribution. So far known only from the type locality, off Sakthikulangara, Kerala State, India, at depths of 10– 15 m.

Remarks. Ciliopagurus grandis n. sp. is similar to C. caparti (Forest, 1952) from the eastern Atlantic, C. albatrossi Forest, 1995 from Hawaii, C. shebae (Lewinsohn, 1969) from the Indo-West Pacific, C. macrolepis Forest, 1995 from Indonesia, and C. liui Forest, 1995 from Japan and China. Shared characters are (Forest 1995): the ultimate segment of the antennular peduncle is more than 0.3 times as long as the shield; transverse ridges on the palms of the chelae are mostly minutely denticulate, lacking distinct tubercles or spines; the palms of the chelipeds have four or more main transverse ridges, interspersed by shorter striae; and the meri of the chelipeds are devoid of prominent tubercles or spines on the ventral surface. However, C. grandis n. sp. is distinctive in the weakly armed antennal acicles, which bear at most one lateral and one or two mesial spines. In the other species, the antennal acicle is normally armed with five or more spines on the mesial margin and with two or more spines on the lateral margin. The simple ocular acicle distinguishes C. grandis n. sp. from C. albatrossi , C. shebae , C. liui and C. macrolepis , as the ocular acicle is bifid in the latter four species. The relatively short antennal acicle, which only slightly overreaches the fourth segment of the antennal peduncle, differentiates C. grandis n. sp. from C. caparti , C. macrolepi s and C. liui . In the latter three species, the antennal acicle reaches nearly to the midlength of the fourth segment of the antennal peduncle. The greatly unequal posterior lobes of the telson, of which the left lobe is roundly subtriangular, separates C. grandis n. sp. from C. caparti , C. shebae and C. liui . Information on the coloration in life or in well-preserved condition is available for C. caparti , C. shebae and C. liui , among the five species considered. Ciliopagurus caparti is distinctive in having longitudinal stripes on the shield (Forest 1995). Ciliopagurus shebae differs from C. grandis n. sp. in the dorsally white carapace (versus generally orange in the shield and pale orange in the posterior carapace), uniformly orange ocular peduncles (versus dorsally white and remainder red), uniformly whitish ambulatory dactyli (versus generally orange with red transverse ridges) and the dark reddish brown abdomen ornamented by white transverse bands (versus generally white). Ciliopagurus liui differs from C. grandis n. sp. in the uniformly orange ocular peduncles and the reddish brown abdomen marked by numerous transverse to longitudinal white lines ( Miyake 1982; Tas rizopagurus krempfi ).

Among the species characterized by the smooth or microscopically denticulate transverse ridges on the chelae, Ciliopagurus krempfi (Forest, 1952) from the Indo-West Pacific also somewhat resembles the present new species in having simple ocular acicles and the short antennal acicles. Nevertheless, C. krempfi is readily distinguished from C. grandis n. sp. by the fewer main transverse ridges on the palms of the chelipeds and the subequal posterior lobes of the telson. In C. krempfi , there are four main, complete transverse ridges on the palm of the cheliped, whereas, there are seven or eight main transverse ridges, of which three or four are interrupted, in C. grandis n. sp. The coloration is also very different between the two: in C. krempfi , the carapace is entirely whitish; the ocular peduncles are uniformly yellow; and the ambulatory dactyli are uniformly yellow, without distinct markings.

From Indian waters, two other congeneric species are known, C. strigatus (Herbst, 1804) and C. tenebrarum ( Alcock, 1905) (Forest 1995) . This new species is the third known from India. Differentiation between the present new species and these two species is easy: C. strigatus differs from C. grandis n. sp. in the multispinose ocular acicle; C. tenebrarum differs from the new species in the presence of small prominent tubercles on transverse ridges on the chelae and the short antennal peduncle only slightly reaching beyond the midlength of the ocular peduncle. The coloration is also very different among the three species. For example, the ocular peduncle is entirely red in C. strigatus (cf. Poupin & Malay 2009) and C. tenebrarum (cf. Alcock 1905), but it is dorsally white in C. grandis n. sp. The chelipeds and ambulatory legs are banded with white or light yellow and red in C. strigatus (cf. Poupin & Malay 2009); banded with light red and dark red, with tips of the distal four segments being white in C. tenebrarum (cf. Alcock 1905); and generally orange with slender dark red bands in C. grandis n. sp.