WILLIAMS AND BABA: SQUAT LOBSTERS FROM THE PACIFIC OCEAN 



well-developed terminal spine, and with second- 

 ary spine on distal margin between them, dorsal 

 rib spiny, lateral rib less so; each propodus 

 slender, with dorsal, dorsolateral, and lateral 

 ridges spiny in proximal half but less so distally, 

 dorsal spines pronounced; each dactyl slender, 

 acute corneous tip preceded by row of 14 or more 

 movable spines on prehensile edge. Chela on 

 slender fifth leg with well-developed cleaning 

 bi'ush (chelae missing on holotype). 



Eggs on holotype + few, large, principal axes 

 measuring 1.3 x 1.6 mm. 



Remarks. — Observations televised during A/um 

 Dive 1845, 18°13'N, 144°42'E, 3,716 m, 6 

 May 1987, Pilot HolUs, Observers Ohta, Kono, 

 included views of Munidopsis that may be this 

 species. 



Munidopsis marianica resembles a number of 

 species in the genus that normally have epipods 

 restricted to the first pereopods, eyespines ex- 

 tending beyond the cornea, and chelipeds lacking 

 a denticulate carina on the distolateral margin of 

 the chela, including M. cmssa Smith, 1885; M. 

 similis Smith, 1885; M. siibsquamosa Hender- 

 son, 1885; M. baruardi Kensley, 1968; M. tnftsi 

 Ambler, 1980; and M. geyeri Pequegnat and 

 Pequegnat, 1970. Munidopsis similis, originally 

 considered to be a variety (subspecies) of M. 

 crassa (see Smith 1885;496), is different from 

 this gi'oup in lacking epipods on all pereopods 

 (Pequegnat and Pequegnat 1970:139). Munidop- 



sis geyeri was synonymized vdth M. subsqimm- 

 osa (see Ambler 1980;26), and M. barnardi from 

 South Africa (Kensley 1968;290) will in all prob- 

 abihty be merged with M. subsquamosa (un- 

 publ. data). Therefore, the remaining three 

 species are compared with the present new 

 species. 



The closest relative to this new species seems 

 to be M. tuftsi, known from off Oregon (Ambler 

 1980:24). The shared characters are relatively 

 long chelipeds, particularly meri that extend 

 nearly to the rostral tip, the anterior half of the 

 carapace that bears tubercles or spines rather 

 than rugae, and the strongly convex postero- 

 median margin of the sixth abdominal segment 

 that distinctly overreaches the lateral lobe on 

 each side. However, M. tuftsi differs from M. 

 marianica — the walking legs are more strongly 

 spinose but the chelipeds are less spiny; the 

 anterior half of the carapace, especially the 

 anterior branchial region, bears distinct dorsal 

 spines; the telson is relatively wide (length- 

 width ratio, 0.71 in the holotype of M. tuftsi, 

 0.79 [x] in M. marianica), the midlateral plate 

 is more markedly convex on the distolateral 

 margin; and the rostrum is distinctly carinate 

 dorsally, relatively high and strongly upcurved. 

 Most clearly different in the 2 species are dactyli 

 of the walking legs (Fig. 36, c); they terminate in 

 a short corneous, curved spine. In M. tuftsi, the 

 ultimate ventral tooth is distinctly closer to the 

 tip of the terminal spine than to the penultimate 



Figure 3. — Munidopsis marianica, paratype ?', USNM 240201: a, anterior carapace with parts of appendages, 

 dorsal; b. dactyl of first walking leg; c, M. tuftsi, holotype cf', USNM 1713:36, dactyl of first walking leg. 



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