Munidopsidae Ortmann, 1898

Ahyong, Shane T., Baba, Keiji, Macpherson, Enrique & Poore, Gary C. B., 2010, A new classification of the Galatheoidea (Crustacea: Decapoda: Anomura), Zootaxa 2676 (1), pp. 57-68 : 63-64

Munidopsidae Ortmann, 1898

( Fig. 2I–O )

Munidopsinae Ortmann, 1898: 1151 .

Shinkaiinae Baba & Williams, 1998: 152 , 155.

Diagnosis. Rostrum well developed, subtriangular or spiniform; supraocular spines absent. Carapace (excluding rostrum) longer than wide; dorsum variously ornamented, smooth, tuberculate, spinose or with transverse striae. Tailfan well developed, not folded against preceding somite; telson distinctly or indistinctly subdivided into multiple plates. Eyes reduced or with well-developed cornea. Antennal peduncle directed anteriorly or anterolaterally. Maxilliped 1 exopod flagellum absent or reduced. Maxilliped 3 pediform; ischium and merus elongate, not expanded mesially; epipod present. Chelipeds subcylindical to ovate in cross-section.

Type genus. Munidopsis Whiteaves, 1874 .

Composition. Extant genera: Galacantha A. Milne-Edwards, 1880 ; Leiogalathea Baba, 1969 ; Munidopsis Whiteaves, 1874 ; Shinkaia Baba & Williams, 1998 .

Fossil genera: Brazilomunida Martins-Neto, 2001 [Upper Cretaceous]; Calteagalathea De Angeli & Garassino, 2006 [Upper Cretaceous]; Eomunidopsis Vía Boada, 1981 [Upper Jurassic to Upper Cretaceous]; Faxegalathea Jakobsen & Collins, 1997 [Lower Paleocene]; Gastrosacus von Meyer, 1851 [Upper Jurassic to Cretaceous]; Munitheities Lőrenthey in Lőrenthey & Beurlen, 1929 [Upper Jurassic]; Palaeomunidopsis Van Straelen, 1925 [Middle Jurassic]; Paragalathea Patrulius, 1960 [Upper Jurassic to Cretaceous].

Remarks. The family Munidopsidae is united by the reduced or absent flagellum on maxilliped 1, and includes the genera formerly comprising the Munidopsinae and Shinkaiinae , and the former galatheid, Leiogalathea . Although Ortmann (1898) formalized the name Munidopsinae, A. Milne-Edwards & Bouvier (1894) had earlier recognized the characteristic synapomorphy of the group through the informal label, “Les Galathéens Non Flagellés”. Other more general distinguishing features of munidopsids include (usually) reduced eyes of most species and dorsal carapace ornamentation. Munidids and galatheids almost always have long, distinct, transverse striae (or minute spinules in Fennerogalathea and Paramunida ) whereas munidopsids generally have short or few striae, and are more commonly tuberculate or squamate.

Four extant and eight extinct genera are included in the Munidopsidae . Although the Mesozoic Eomunidopsis and Paragalathea have been considered to be galatheines (now galatheid) ( Schweitzer & Feldmann 2000), we follow Collins et al. (1995) in a munidopsid alignment. Similarly, Calteagalathea is also regarded as a munidopsid. Calteagalathea , Eomunidopsis and Paragalathea resemble many species of Munidopsis , especially in the squamate, tuberculate or rippled carapace surface, and elongate, distally dentate rostrum with a median ridge. Moreover, Calteagalathea , Eomunidopsis and Paragalathea are readily accommodated within the current concept of Munidopsis , indicating that further refinement of the generic classification is required to harmonize neontological and palaeontological taxonomies.

Leiogalathea ( Fig. 2M ) was regarded as a galatheid on the basis of its general Galathea -like habitus, small size and well-developed eyes, although maxilliped 1 has a reduced flagellum. However, molecular phylogenetic analyses ( Ahyong et al. 2009) found strong support for a close relationship between Leiogalathea and a clade containing Munidopsis , Galacantha and Shinkaia . Additionally, sternite 4 of Leiogalathea is narrowly triangular with a narrow point of contact with sternite 3, which is more typical of Munidopsis and Galacantha than Galatheidae , in which sternite 3 is fully appressed to the anterior margin of sternite 4.

Shinkaia ( Fig. 2O ) was originally assigned to its own subfamily alongside the Munidopsinae and Galatheinae ( Baba & Williams 1998) . Shinkaia shares the suppression of the flagellum of the maxilliped 1 exopod with other munidopsids, but differs in numerous autapomorphies, such as the densely setose sternum and short rather than elongated epipods on the pereopods ( Baba & Williams 1998). Ahyong et al. (2009) found a paraphyletic relationship between Shinkaia and other munidopsids, and as such did not support separate subfamily status for the former. Although the Shinkaiinae may yet prove to be valid after more extensive analysis of the munidopsid genera is completed (in collaboration with J. Taylor and N. Andreakis), it is presently regarded as a junior synonym of Munidopsidae .

The Munidopsidae include the deepest dwelling galatheoids, usually occupying slope to abyssal depths, although one species, M. polymorpha , lives as shallow as 2 m in submarine caves ( Baba et al. 2008). The majority of munidopsids have reduced or degenerate eyes, reflecting their deep bathymetric preference ( Alcock 1902).

Figures

FIGURE 2. Carapace and abdomen (A–N) and anterior carapace (O) of selected Galatheoidea. Galatheidae: A, Galathea tropis Baba, 2005; B, Lauriea siagiani Baba, 1994; C, Alainius crosneri Baba, 1991; D, Allomunida magnicheles Baba, 1988. Munididae fam. nov.: E, Munida exilis Ahyong, 2007; F, Agononida eminens (Baba, 1988); G, Bathymunida ocularis Baba & de Saint Laurent, 1996; H, B. frontis Baba & de Saint Laurent, 1996; Munidopsidae: I, Munidopsis pycnopoda Baba, 2005; J, M. norfanz Ahyong, 2007; K, M. bractea Ahyong 2007; L, M. laciniosa Baba, 2005; M, Leiogalathea laevirostris (Balss, 1913); N, Galacantha rostrata A. Milne-Edwards, 1880; O, Shinkaia crosnieri Baba & Williams, 1998. Figure sources: A, I, L (Baba 2005); B (Baba 1994); C (Baba 1991); D (Baba 1988); E, J, K, M (Ahyong 2007); F, O (Baba et al. 2009); G, H (Baba & de Saint Laurent 1996); N (Baba & Poore 2002).