Lithodes paulayi, Macpherson, Enrique & Chan, Tin-Yam, 2008

Macpherson, Enrique & Chan, Tin-Yam, 2008, Some lithodid crabs (Crustacea: Decapoda: Lithodidae) from Taiwan and adjacent waters, with the description of one new species from Guam, Zootaxa 1924, pp. 43-52 : 44-47

Lithodes paulayi n.sp.

( Figs 1–3 , 5 c)

Material examined. Guam: 3–4 miles South, 27.09.1998, trap, 740 m: male holotype 113 × 102 mm (UF 2283). — 1.5 miles off Maizo, 11.1998, 740 m: 1 male paratype, 45 × 39 mm.

Etymology. This new species is named after Gustav Paulay, who kindly entrusted us with the study of his material from Guam.

Description. Carapace more or less pyriform, slightly longer than broad. Regions well defined. Gastric region convex, more prominent than other areas, with two pairs of strong spines, the anterior pair being larger than the posterior. Gastric and cardiac regions separated by deep transverse furrow. Cardiac region armed with 2 spines similar in size to posterior pair of gastric spines. Two long spines present on intestinal region. Branchial regions as prominent as cardiac, each with 2 long spines, the anterior spine directed slightly laterally, the second spine, slightly smaller than the anterior one, at a level posterior to the cardiac spines. Each region with numerous small granules.

Rostrum with anterior projection long and bifid. Two long dorsal spines and one strong and curved basal spine. The anterior projection is directed upward in its proximal part (before dorsal spines), being nearly horizontal in its distal part. The anterior projection is 0.8 times the carapace length.

External orbital spines well developed, not overreaching end of eyes. Anterolateral spines longer than external orbital. Space between anterolateral and hepatic spines without spines. Hepatic spines very long. Each branchial border with one strong spine, clearly smaller than hepatic spine, and 11 or 12 small spines. Second abdominal segment with a few small spines on the median plate and external edges of plates.

Eyestalks without dorsal spines.

Basal segment of antennal peduncle with spine on outer terminal angle, not exceeding first half of penultimate segment.

Chelipeds with merus bearing strong spines on the terminal border. Carpus with strong spines on dorsal and outer surfaces. Palm armed with several poorly defined rows of thick but short spines on dorsal, outer and ventral borders. Fingers 1.4 times palm length, with numerous tufts of setae. Some small spines scattered on segments.

Walking legs long, third longer than first and second. Third walking leg 3 times carapace length. On third walking leg, coxa with few short spines on ventral side and terminal border, basis-ischium with several short spines on terminal border. Merus slightly longer than carapace length, and 9 times longer than high. Several spines on extensor (dorsal), posterior and flexor (ventral) borders, with some smaller spines scattered in between, distal spine on extensor border strongest than others. Carpus 0.5 times merus length, with long spine on extensor and terminal border and some small spines scattered on extensor and posterior borders. Propodus 0.9 times shorter than merus, about 12.5 times longer than high, and twice length of dactylus, with some spines on extensor border and some smaller ones on outer surface and flexor border. Dactylus rounded in cross section, with some spines on base and along extensor margin.

Va r ia ti o n s. The male paratype has all spines clearly longer than in the holotype ( Figs 2 b, d, 3d). Nevertheless, the positions of the largest spines on the carapace are similar in both specimens. The proportions of the articles of the walking legs are also similar.

Coloration. Generally reddish.

Remarks. Lithodes paulayi n. sp. belongs to the group of species possessing a carapace with some long spines, e.g., L. longispina Sakai, 1971 from the waters off Japan and the central Pacific, and L. megacantha Macpherson, 1991 from French Polynesia (see Sakai 1971; Macpherson 1991; Ikeda 1998). The new species is readily distinguishable from L. longispina by the following:

— Each branchial region has two long dorsal spines and only one long marginal spine in the new species. In L. longispina each branchial region has only one long dorsal spine, situated at level of cardiac spines, and two long marginal spines.

— The rostrum is longer in the new species than in L. longispina , clearly shown when similar sized specimens of the two species are compared.

— The distolateral spine of the basal segment of the antennal peduncle does not exceed the proximal half of the penultimate segment in the new species, whereas it reaches the end of this segment in L. longispina .

— The walking legs are more slender in the new species than in L. longispina . The merus and propodus of the third walking leg are 9 and 12.5 times longer than high, respectively. In males of L. longispina these values are about 7 and 9 times respectively.

— The lateral surface of the walking legs is covered with many small spines in L. longispina , whereas these spines are almost absent in the new species.

The second closely related species, L. megacantha , has the number and position of the long branchial spines similar to L. longispina , and thus, L. paulayi is similarly easily distinguished. Furthermore, the spines on the carapace and walking legs are clearly longer in L. megacantha than in the new species. The comparison between similar sized specimens of the two species clearly showed this difference (see Macpherson 1991).

Figures

FIGURE 1. Lithodes paulayi n. sp., holotype male 113 × 102 mm, Guam. (a) carapace, dorsal. (b) lateral view of anterior carapace and rostrum. (c) dorsal view of right anterolateral carapace and appendages. (d) lateral view of right anterolateral carapace and appendages. (e) right third walking leg, dorsal. Scales = 1 cm.

FIGURE 2. Lithodes paulayi n. sp., Guam. (a, c) holotype male 113 × 102 mm. (b, d) paratype male 45 × 39 mm. (a – b) dorsal view of carapace. (c – d) lateral view of carapace.

FIGURE 3. Lithodes paulayi n. sp., Guam. (a – c) holotype male 113 × 102 mm. (d) paratype male 45 × 39 mm. (a) dorsal view of left basal segment of antennal peduncle. (b) lateral view of right chela. (c – d) right third walking leg, dorsal.

FIGURE 5. Dorsal view. (a) Neolithodes nipponensis Sakai, 1971, male, Taiwan, Stn CD 228. (b) Lithodes turritus Ortmann, 1892, male, Taiwan, Dasi fishing port. (c) Lithodes paulayi n. sp., holotype male, Guam. (d) Paralomis dofleini Balss, 1911, male, Taiwan, Dasi fishing port. (e) Paralomis arae Macpherson, 2001, female, Taiwan. f, Paralomis truncatispinosa Takeda & Miyake, 1980, broken carapace, Taiwan, Stn CD 231.