A New Species of <I>Uroptychus </I> (Decapoda: Anomura: Chirostylidae

BULLETIN OF MARINE SCIENCE. 88(1):113–118. 2012 NEW TAXA PAPER http://dx.doi.org/10.5343/bms.2011.1071

A new species of Uroptychus (Decapoda: Anomura: Chirostylidae) from Taiwan

Patricia Cabezas, Chia-Wei Lin, and Tin-Yam Chan

Abstract A new species of squat lobster, Uroptychus parilis sp. nov., is described and illustrated from two female specimens collected in Taiwan. The new species is closely related to Uroptychus babai Ahyong and Poore, 2004, and was misidentified as it before. Uroptychus parilis sp. nov. is characterized by having the lateral margins of the carapace smooth and slightly irregular, the thoracic sternite 4 produced into a sharp spine which reaches the anterior end of emargination of the thoracic sternite 3, and the antennal scale falling short to slightly overreaching apex of fifth peduncle segment.

The squat lobsters of the family Chirostylidae are typically distributed in shelf and slope habitats, often in association with soft corals such as antipatharians, alcyona- ceans, and gorgonaceans (Baba 2005, see also Schnabel and Ahyong 2010 for recent taxonomic definition of this family). To date, the family includes five genera and over 175 species worldwide (Baba and Lin 2008, Baba et al. 2008, Baba and Macpherson 2011, Poore and Andreakis 2011), with Uroptychus being the most speciose genus. Recent taxonomic studies have greatly expanded the number of chirostylid known species (Baba 2005, Schnabel 2009), and potentially many more new species are to be discovered in the Indo-West Pacific (e.g., Schnabel et al. 2011). The Chirostylid fauna from Taiwan has been well studied thanks to the extensive deep-sea surveys completed over the last decade (Baba et al. 2009). In total, 17 chirostylid species be- longing to the genera Chirostylus, Uroptychodes, and Uroptychus have been recorded in the region and the presence of the genus Gastroptychus is also likely (Baba et al. 2009). However, recent findings show that material referred to Uroptychus babai Ahyong and Poore, 2004 by Baba et al. (2009) is misidentified and actually represent a new species. The present work reports this finding.

Material and Methods

The material used in the present study is deposited in the collections of the National Taiwan Ocean University (NTOU). The terminology used mainly follows Ahyong and Poore (2004) and Baba (2005). Measurements of specimens, given in millimetres, represent the postorbital carapace length. The abbreviations used in the text are as follows: M, male; F, female; Mxp, maxilliped; ovig., ovigerous; P1, pereopod 1, cheliped; P2–P4, pereopods 2–4, first to third walking legs; CD, the Otter Trawl Le Drezen type Solo Hard Bottom; and stn, station.

Results

Genus Uroptychus Henderson, 1888

Uroptychus parilis new species (Fig. 1)

Uroptychus babai.—Baba et al. 2009: 38, figs. 30–31 (not U. babai Ahyong and Poore, 2004). Material Examined.—Holotype, stn CD230, Taiwan, off southwestern coast, 22°19.32Ń, 120°3.3É, 795–840 m, 30 August, 2003, 1 ovig. F 11.1 mm (NTOU A01079). Paratype, stn CD231, Taiwan, off southwestern coast, 22°14.32Ń, 119°58.78É, 951–1062 m, 31 August, 2003, 1 F 8.0 mm (without chelipeds, NTOU A01087). Etymology.—Named parilis, meaning “like” or “same” in Latin, in reference to the similarity to another species of the genus (U. babai in the present case). Diagnosis.—Carapace slightly broader than long (excluding rostrum); lateral margins smooth and slightly irregular, distinctly convex, broadest posterior to midlength, ridged along posterior half, with distinct, anteriorly directed anterolateral spine. Rostrum sharply triangular, margins unarmed. Thoracic sternite 4 produced into a sharp spine reaching anterior end of emargination of thoracic sternite 3. Basal antennal segment with small lateral spine; fourth and fifth peduncle segments unarmed; fifth segment about twice length of fourth segment. Antennal scale varying from falling short to slightly overreaching apex of fifth peduncle segment. P1 slender and about 6 times carapace length. Pereopods 2–4 propodi not broadened distally, with 1 or 2 movable spine on distal flexor margin; dactyli distally curved with 18–21 small, fixed spines on flexor margin, penultimate broader than others. Description.—Carapace.—Slightly broader than long (excluding rostrum). Lateral margins smooth and slightly irregular, distinctly convex, broadest posterior to midlength; ridged along posterior half, with distinct, anteriorly directed anterolateral spine. Rostrum sharply triangular, slightly curving upwards, 1.5 times longer than basal width, half length of remaining carapace, margins unarmed; dorsum sparse- ly setose. Outer orbital angle produced into triangle tooth, not extending beyond anterolateral spine. Dorsum carapace densely covered with fine setae, unarmed. Anterior margin of pterygostomian flap produced into a spine (Fig. 1A,B). Sternum.—Sternal plastron broader than long, slightly widening posteriorly. Thoracic sternite 3 (at base of maxilliped 3) not depressed, anterior margin with deep V-shaped emargination, outer lobes of emargination obtuse. Thoracic sternite 4 (at base of pereopod 1) produced into a sharp spine reaching level of anterior end of emargination of stenite 3 (Fig. 1C). Abdomen.—Tergites unarmed, with fine setae. Telson about half as long as broad; distal portion posteriorly emarginate, about twice length of proximal portion (Fig. 1A,D). cabezas et al.: new species of chirostylid from taiwan 115

Figure 1. Uroptychus parilis sp. nov., holotype ovigerous female, 11.1 mm, NTOU A01079, Taiwan. (A) Carapace and abdomen, dorsal, setae omitted from right side; (B) anterior carapace, right lateral, setae omitted; (C) sternum, ventral; (D) telson, dorsal; (E) antenna, left ventral; (F) Mxp 3, right lateral; (G) crista dentata, right lateral; (H) P1, right dorsal; (I) P1, palm and polex, right dorsal; (J) P1 merus, proximal left ventral; (K) P2, right lateral, setation similar to P4 and mostly omitted; (L) P3, right lateral, setation similar to P4 and mostly omitted; (M) P4, right lateral; (N) P2 dactylus, right lateral. Scales: 5 mm (scale 1 for A–C, H, J–M; scale 2 for D, F, I; scale 3 for E, G, N). 116 BULLETIN OF MARINE SCIENCE. VOL 88, NO 1. 2012

Eye.—Cornea not dilated, about one-third length of peduncle; reaching half of rostrum (Fig. 1A). Antenna.—Basal segment with small lateral spine. Flagellum about twice as long as peduncle. Fourth and fifth peduncle segments unarmed; fifth segment about twice as long as fourth segment. Antennal scale wider than opposite peduncular segments, varying from falling short to slightly overreaching apex of fifth peduncle segment (Fig. 1E). Maxilliped 3.—Dactylus, propodus, carpus, and merus unarmed. Crista dentata evenly serrated on proximal three quarters of ischium, not extending onto basis (Fig. 1F,G). Pereopod 1 (cheliped).—Long and slender, densely covered with setae, about 6 times carapace length. Propodus with palm about 10 times as long as height, about 3 times as long as pollex; unarmed. Fingers crossing, occlusal margins dentate; occlusal margin of dactylus with obtuse process proximally; occlusal margin of pollex with low prominence at midlength. Merus and carpus unarmed. Carpus 1.6 times and about 0.7 times as long as merus and propodal palm, respectively. Ischium with triangular spine on outer margin (Fig. 1H–J). Pereopods 2–4.—Densely covered with setae, similar and slightly decreasing in length posteriorly. Meri with distal spine on ventral margin; length 0.9–1.2 times that of propodus. Carpi unarmed. Propodi not broadened distally, with 1 or 2 movable spines on distal flexor margin. Dactyli distally curved with row of obliquely inclined small fixed spines on flexor margin, 18–20 spines in P2, 19–21 spines in P3, and 21 spines in P4; penultimate broader than others. Carpus of P2-4 about 0.4 merus and 0.5 propodus length (Fig. 1K–N). Ovum.—1.2 mm diameter. Color.—Orange-red overall, whitish at junctures of segments and distal parts of dactyli on P1-4; tailfan translucent (see Baba et al. 2009: fig. 30). Egg whitish. Distribution.—Known only from southwestern Taiwan at depths between 795 and 1062 m. Remarks.—Uroptychus parilis sp. nov. belongs to the group of species with rostrum distinctly longer than broad, carapace broader than long, dactyli of walking legs with > 8 spines along flexor margin, and fourth and fifth segments of antennal peduncle without distal spine. Uroptychus parilis sp. nov. closely resembles U. babai from southeastern Australia and Madagascar. Material of the present new species from Taiwan was compared with two U. babai paratypes (New South Wales, east of Broken Bay, 951 m, 1 M 18.2 mm, 1 ovig. F 15.4 mm, AM P53248). Comparison of adults between these two species reveals that the lateral carapace margins are smooth and slightly irregular in the new species, but clearly crenulated in U. babai. Furthermore, the antennal scale extends beyond the fifth peduncle segment in U. babai, but falling short to slightly overreaching the latter in the new species. More importantly, the thoracic sternite 4 has the anterolateral margin produced into a spine in U. parilis sp. nov., but this spine is lacking in U. babai. The shape of the thoracic stenite 4 is considered to be very constant in Uroptychus (see Ahyong and cabezas et al.: new species of chirostylid from taiwan 117

Poore 2004, Baba 2005). Thus the present Taiwanese form, though with only two specimens known so far, is determined to be distinct from the true U. babai. Uroptychus parilis sp. nov. is also allied to two other southern Australian species, Uroptychus longvae Ahyong and Poore, 2004 and Uroptychus patulus Ahyong and Poore, 2004, by the V-shaped anterior emargination of thoracic sternite 3. Nevertheless, the new species can be readily distinguished from U. longvae in having the antennal scale falling short or slightly overreaching the apex of the fifth peduncle segment instead of extending to about midlength; and from U. patulus in having 18–21 fixed spines instead of 20–30 short triangular teeth on the flexor margin of the dactyli of the walking legs. There are some resemblances of the new species to Uroptychus maori Borradaile, 1916 from New Zealand. However the rostrum is slightly deflected ventrally in the latter species, instead of curving upwards, and the P1 is about 2.5–3 times carapace length in U. maori but about 6 times in U. parilis sp. nov.

Acknowledgments

We sincerely thank E Macpherson of the Centro de Estudios Avanzados de Blanes (CSIC) and K Baba of the Kumamoto University for kindly reviewing the manuscript. We thank C Noreña and C Toledo from the Museo Nacional de Ciencias Naturales (CSIC) for assis- tance in preparing the line drawings. We are also indebted to S Ahyong from the Australian Museum for loaning us paratypes of Uroptychus babai. This work was supported by the National Science Council, Taiwan, ROC, Academia Sinica, Taiwan, ROC, the Ángel Cabrera award from the Museo Nacional de Ciencias Naturales, CSIC, and by the MEC project CTM 2008-00496.

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Date suBmitted: 11 July, 2011. Date AccePted: 6 september, 2011.

Addresses: (pc) Museo Nacional de ciencias Naturales (MNcN-csIc), José Gutiérrez Abascal, 2, 28006, Madrid, spain. (c-wl) 1. National Museum of Marine Biology and Aquarium, 2 houwan road, checheng, pingtung 944, taiwan, roc. 2. Institute of Marine Biodiversity and Evolutionary Biology, National Don hwa University, No. 1, sec. 2, Da hsueh rd., shoufeng, hualien 97401, taiwan, roc. (t-yc) Institute of Marine Biology and center of Excellence for Marine Bioenvironment and Biotechnology, National taiwan ocean University, 2 pei-Ning road, Keelung 20224, taiwan, roc. corresPonding Author: (c-wl) E-mail: .