Munida lanciaria, Cabezas, Patricia, Lin, Chia-Wei & Chan, Tin-Yam, 2011

Cabezas, Patricia, Lin, Chia-Wei & Chan, Tin-Yam, 2011, Two new species of the deep-sea squat lobster genus Munida Leach, 1820 (Crustacea: Decapoda: Munididae) from Taiwan: morphological and molecular evidence, Zootaxa 3036, pp. 26-38 : 29-31

Munida lanciaria sp. nov.

( Fig. 1 )

Munida militaris . — Baba et al. 2009: 173 (in part). [Not Munida militaris Henderson, 1885 ]

Material examined. Holotype, “ TAIWAN 2003”, stn CP214, 24°29’N, 122°13’E, 490–1027 m, 27 August 2003, 1 M 7.5 mm ( NTOU A00707). Paratypes, “ TAIWAN 2003”, stn CP211, 24°41’N, 122°11’E, 517–518 m, 27 August 2003, 1 F 7.1 mm ( NTOU A00697); stn CP214, 24°29’N, 122°13’E, 490–1027 m, 27 August 2003, 1 F 7.4 mm ( NTOU A00715).

Etymology. From the Latin “lanciarius”, which means “Roman light infantry”, in reference to the less armed carapace (i.e. with less spines) of the new species as compared to its closely related species M. militaris , for which the Latin name means “of soldiers”.

Diagnosis. Dorsal surface of carapace with row of 7 or 8 epigastric spines. Five spines on branchial margin of carapace. Rostrum spiniform. Second abdominal somite with 4, 6 or 8 spines on anterior ridge. Lateral part of seventh sternite smooth. Cornea moderately large with maximum corneal diameter about 1/3 distance between anterolateral spines. Distomesial spine of antennular basal segment shorter than distolateral spine. Distomesial spine of antennal basal segment reaching second segment; distomesial spine of second segment not reaching end of third segment; third segment armed with distomesial spine and fourth segment unarmed. Mxp3 merus unarmed on extensor margin. P1 carpus 2.5 times longer than broad; lateral margin of fixed finger with 3 subterminal spines in the male and with row of lateral spines continued onto fixed finger in females, mesial margin of movable finger with 1 basal spine. P2 propodus about 1.6 times length of dactylus, flexor margin with 6–8 movable spinules along entire flexor margin.

Description. Carapace: Approximately 1.2 times longer than wide, slightly convex dorsally. Secondary striae absent. Several short striae present on branchial and parahepatic regions. Epigastric region with row of 7 or 8 spines. Frontal margins slightly oblique. Lateral margins slightly convex. Anterolateral spine well-developed, situated at anterolateral angle, reaching sinus between rostral and supraocular spines. Second marginal spine anterior to cervical groove very small. Branchial margins with 5 spines decreasing in size posteriorly. Rostrum spiniform, more than half as long as remaining carapace. Supraocular spines well-developed, not reaching midlength of rostrum and end of cornea, subparallel ( Fig. 1 a).

Abdomen: Second somite with 4, 6 (holotype) or 8 spines on anterior ridge and followed by 2 uninterrupted transverse striae ( Fig. 1 a).

Sternum: Fourth to sixth thoracic sternites smooth, lateral part of seventh sternite without granules. Anterior part of fourth sternite narrower than third sternite, slightly concave medially and broadly contiguous with posterior margin of third sternite. Transverse ridges on fifth to seventh sternites obtuse ( Fig. 1 b).

Eyes: Moderately large, maximum corneal diameter about 1/3 distance between anterolateral spines ( Fig. 1 a).

Antennule: Basal segment (distal spines excluded) about 0.3 times carapace length, elongate, slightly less than twice as long as broad, reaching or slightly overreaching distal end of cornea; distomesial spine shorter than distolateral one; 2 spines on lateral margin, proximal small, located near middle of segment, distal long, not reaching end of distolateral spine ( Fig. 1 c).

Antenna: First segment with distomesial spine reaching end of second segment (without spines); second segment with 2 distal spines and 1 mesial spine, distomesial spine slightly longer than distolateral spine, not reaching end of third segment; third segment with distomesial spine; fourth segment unarmed ( Fig. 1 c).

Maxilliped 3: Ischium about 1.2 times length of merus (measured along dorsal margin), distoventrally bearing 1 spine. Merus with 2 spines on flexor margin, proximal one slightly longer than distal one; extensor margin unarmed ( Fig. 1 d).

Pereopod 1 (cheliped): Squamate, more than twice carapace length and covered with simple setae. Merus as long as carapace, twice carpus length and 1.3 times palm length; with 4 rows of spines, those on mesial border stronger. Carpus 2.5 times longer than broad, with row of spines on mesial margin and dorsal surface, and several short spines on lateral side. Palm slightly longer than fingers, with several spines scattered on mesial and dorsal sides, and row of lateral spines continued onto fixed finger in females. Fingers distally curving and crossing, ending in sharp point; fixed finger with lateral margin bearing 3 subterminal spines that may continue along the entire lateral margin and with dense iridescent setae in females; movable finger only with a small spine near base ( Fig. 1 e).

Pereopods 2–4 (walking legs): P2 nearly 1.3 times carapace length. Merus shorter than carapace, 7–8 times as long as high, 4 times carpus length, and 1.5 times propodus length; propodus about 6 times as long as high, and 1.7 times longer than dactylus ( Fig. 1 f), dorsal and ventral margins with row of spines. Carpus with 3-4 dorsal spines and 1 distoventral spine. Propodus about 1.6 times dactylus length, with 6 or 7 movable ventral spinules. Dactylus slightly curving distally, with 6–8 movable spinules along entire flexor margin ( Fig. 1 g). P3 0.9 times as long as P2, spination and segment proportions similar to those of P2 but generally less spinous ( Fig. 1 h). P4 0.7 times as long as P2, merus nearly half as long as that of P2 and without dorsal spine; carpal dorsal margin only with distal spine ( Fig. 1 i). Merocarpal articulation of P2 not reaching level of merocarpal articulation of P1; merocarpal articulation of P4 ending at level of anterior branch of cervical groove.

Colour in life. Unknown.

Distribution. Known only from Taiwan between 490–1027 m deep (as compare to the depth ranges of 190– 1027 m for the true M. militaris material from Taiwan).

Remarks. Munida lanciaria sp. nov. closely resembles M. militaris Henderson, 1885 and M. benguela (de Saint Laurent & Macpherson 1988) in having large eyes, carapace without secondary striae, branchial margin with 5 spines, second abdominal segment with row of spines, distomesial spine at basal segment of antennule shorter than distolateral spine, and lateral parts of seventh thoracic sternite smooth. Although the type material of M. militaris included at least three species, its taxonomic status was fixed through the lectotype section ( Baba & Macpherson 1991). The new species differs from M. benguela and M. militaris in lacking parahepatic, branchial dorsal and postcervical spines. Moreover, the third segment of the antennal peduncle in M. lanciaria sp. nov. has a distomesial spine, which is absent in M. militaris and M. benguela . The P1 carpus is also narrower in M. lanciaria sp. nov. (length-breadth ratio 2.5 versus 1.6–1.7 in M. militaris and M. benguela ). Munida lanciaria sp. nov. further differs from M. militaris in the distomesial spine of basal antennular segment being much shorter than the distolateral spine (versus subequal or slightly shorter in M. militaris ); having fewer flexor spinules at the dactyli of the walking legs (6–8 in M. lanciaria sp. nov. versus 10 in M. militaris ).

Figures

FIGURE 1. Munida lanciaria sp. nov., holotype male 7.5 mm (NTOU A 00707) Taiwan. a, carapace and abdomen, dorsal view. b, sternum. c, right antennule and antenna, ventral view. d, right maxilliped 3, lateral view. e, left P 1, dorsal view, setae omitted. f, right P 2, lateral view. g, dactylus, right P 2, lateral view. h, right P 3, lateral view. i, right P 4, lateral view. Scales: a – d, g = 1 mm; e – f, h – i = 5 mm.