Eumunida chani, Baba, Keiji & Lin, Chia-Wei, 2008

Baba, Keiji & Lin, Chia-Wei, 2008, Five new species of chirostylid crustaceans (Crustacea: Decapoda: Anomura: Chirostylidae) from Taiwan, Zootaxa 1919, pp. 1-24 : 2-5

Eumunida chani sp. nov.

( Figs. 1–3 )

Type material. Holotype: NTOU A00850 , female (6.0 mm), E Taiwan, Stn DW 45, 22°48.3’N, 121°27.4'E, 423–439 m, 2 Aug 2000.

Diagnosis. Carapace with distinct transverse ridges. Lateral margin with 2 strong spines in front of posterior cervical groove, anterior spine half as long as lateral supraocular spine. Sternite 3 with 2 distally laciniate submedian processes. Sternite 4 with strong spine on each side. Mxp3 merus with small spine slightly distal to midlength of flexor margin. Abdomen with 3 transverse ridges on tergites 2–3, 2 on tergites 4–5. Pleuron of somite 2 with 4 short longitudinally arranged ridges. P1 merus with 3 rows of spines, mesial spines larger; carpus with 2 distal spines; palm with row of 4 ventromesial spines, barely discernible from dorsal view, lacking pad of densely packed setae on ventral surface. P4 merus with row of 5 small spines along midline of lateral surface.

Description. Carapace as long as broad. Dorsal surface with distinct transverse ridges: 6 ridges on anterior half; first (anteriormost) ridge placed between anteriormost of 3 hepatic spines, second between median hepatic spines, each medially interrupted and preceded by anteriorly convex ridge in midline; second ridge followed by another such ridge in same way; 7 ridges on posterior half; anterior branchial region with small scale-like ridges on lateral portion. Anterior and posterior cervical grooves distinct. Lateral margins convex, with 6 spines: 2 strong spines in front of and 4 posteriorly diminishing spines behind posterior cervical groove; first (anterior-most) spine subequal to second and about half as long as lateral supraocular spine. Rostral and mesial supraocular spines broken, lateral supraocular spine reaching end of cornea.

Sternal plastron slightly longer than broad, lateral extremities divergent posteriorly to sternite 6, sternite 7 as broad as sternite 6. Sternite 3 anteriorly with 2 submedian processes, each distally laciniate. Sternite 4 with strong anteriorly directed spine on each side.

Abdomen with 3 transverse ridges on tergites 2–3, 2 on tergites 4–5, and 3 interrupted ridges on tergite 6. Pleuron of somite 2 with 4 short transverse or oblique ridges arranged longitudinally; pleura of somites 3–5 with single ridge. Telson 0.63 as long as broad; posterior lobe as broad as and 1.5 times longer than anterior lobe, posterior margin distinctly emarginate.

Antennal peduncles broken. Article 1 with small lateral spine; article 3 with spine slightly overreaching end of article 4.

Mxp3 basis with obsolescent denticles on mesial ridge. Ischium with 2 or 3 denticles on flexor distal margin; crista dentata with 14 (left) or 11 (right) denticles. Merus with small spine distal to midlength of flexor margin.

P1 more than 4.5 times longer than carapace (distal half of dactylus broken, lost, excluded), with sparse setae. Merus 2.3 times longer than carapace; 3 rows of spines: 1 dorsomesial, 1 ventromesial and 1 dorsal, mesial spines larger. Carpus with 2 distal spines only: 1 dorsomesial, 1 dorsoventral. Palm 8 times as long as broad, 4 times longer than carpus, ventrally with row of 4 spines along mesial margin, without pad of densely packed setae on ventral surface. Fingers broken.

P2–4 with sparse stiff setae. Meri successively shorter posteriorly (P3 merus 0.93 P2 merus, P4 merus 0.84 P3 merus), subequally broad on P2–4; length-breadth ratio, 7.6 on P2, 5.8 on P3, 5.0 on P4; merus-propodus length ratio, 1.15 on P2, 1.00 on P3, 0.85 on P4; dorsal crests with 9, 11, 10 spines on P2, P3, P4 respectively; lateral surface with row of 5 spines in midline on P4, spineless on P2 and P3; ventrolateral margin with distal spine. P2 merus subequal to carapace length. Carpi subequal; carpus-propodus length ratio, 0.29 on P2, 0.26 on P3, 0.27 on P4; extensor margin with 5 proximally diminishing spines on P2–3, a few additional small spines on P4. Propodi slightly shorter on P2 than on P3 and P4; length-breadth ratio, 8.8 on P2, 9.4 on P3, 0.90 on P4; flexor margin with pair of terminal spines preceded by 5 or 6 movable spines. Dactyli longer than carpi; dactylus-propodus length ratio, 0.37 on P2, 0.40 on P3, 0.38 on P4; flexor margin with 6 or 7 movable spines.

Color in life. Body and appendages pale orange.

Etymology. The species is dedicated to Tin-Yam Chan for his efforts in coordinating the catalog series of Taiwanese crustaceans.

Remarks. Since de Saint Laurent & Poupin (1996) reviewed the genus from the Pacific and provided a key to species, Macpherson (2006) described Eumunida spinosa , new species, from New Caledonia. Both Eumunida spinosa and E. chani fail to key out in couplet 3 in de Saint Laurent & Poupin’s (1996) key to species by lacking a ventral pad of densely packed setae on P1 palm. Eumunida chani is distinguished from E.

spinosa by having less spinose P1, especially the carpus with two instead of three distal spines, and the palm with one row (ventromesial) instead of two rows (ventromesial and ventrolateral) of spines. The bispinose P1 carpus and the sternite 4 with distinct lateral spines link E. chani to E. annulosa de Saint Laurent & Macpherson, 1990 from New Caledonia and Chesterfield Islands. However, E. chani is easily distinguished from that species by lacking a ventral pad on the P1 palm. The sole specimen of the present species is larger than the smallest of the type series of E. annulosa , so it is inconceivable that the lack of ventral pad on P1 is attributable to variation or immaturity. In addition, they also differ in the following: (1) the carapace lateral spine directly behind the anterior cervical groove in E. annulosa is followed behind by a small spine, which is absent in E. chani ; (2) the abdominal tergite 2 in E. annulosa bears additional setiferous ridges other than three principal ridges as in E. chani .

Distribution. Known only from the type locality off E Taiwan, in 423– 439 m.

Figures

FIGURE 1. Eumunida chani n. sp., holotype female, NTOU A 00850. A, carapace and abdomen, dorsal. B, sternal plastron. C, same, anterior part. D, antenna, right, ventral. E, Mxp 3, proximal and distal parts omitted, left, lateral. F, P 1, dorsal. G, same, ventral. Scales = 1 mm.

FIGURE 2. Eumunida chani n. sp., holotype female, NTOU A 00850. A, Telson. B, P 2, left, lateral. C, same, distal part, lateral. D, P 3, right, lateral. E, P 4, right, lateral. F, same, distal part, lateral. Scales = 1 mm.

FIGURE 3. Eumunida chani sp. nov., holotype, female (6.0 mm), NTOU A 00850.