Cryptochiridae, Paulson, 1875

GUINOT, DANIÈLE, TAVARES, MARCOS & CASTRO, PETER, 2013, Significance of the sexual openings and supplementary structures on the phylogeny of brachyuran crabs (Crustacea, Decapoda, Brachyura), with new nomina for higher-ranked podotreme taxa, Zootaxa 3665 (1), pp. 1-414 : 98-99

Family Cryptochiridae

Because the rarity and small size of males, the male gonopores have not been described in detail, the only description is apparently that of Utinomiella dimorpha ( Henderson, 1906) by Henderson (1906: 218, pl. 8, fig. 8, as Cryptochirus dimorphus ), who figured two openings “on the small sternal pieces belonging to the last pair of legs”, about in the middle of sternite 8 and close to the P5 coxae ( Fig. 58F ). The penis is unknown, no “genital papillae” having been observed by Potts (1915: 60, fig. 13) in his detailed study of a male Hapalocarcinus marsupialis . The male gonopore was simply indicated as sternal by Utinomi (1944: 695, 727, as Hapalocarcinidae ), Fize (1956: 21, as Hapalocarcinidae ), and Balss (1957: 1672, as Hapalocarcinidae ). Additional information is absent from the subsequent extensive studies by Fize & Serène (1957), Kropp (1988 a, b, 1989, 1990, 1994, 1995), and Kropp & Manning (1987, 1996). According to Potts (1915: 59, pl. 2, fig. 12) and Fize (1956: 8) each testis of Hapalocarcinus marsupialis , which is visible through the soft, transparent carapace, was so voluminous (full of spermatozoa, not contained in spermatophores) that, in contrast to other brachyurans, the vas deferens could not be recognised. In Cryptochirus coralliodytes examined here, the male gonopore, from which the penis emerges as a papilla, is distant from suture 7/8, thus located posteriorly in relation to the small sternite 8, and close to the P5 coxa. A male gonopore on sternite 8 close to the P5 coxa has been observed in Fungicola fagei (Fize & Serène, 1956) (S. van der Meij, pers. comm. 2011).

The Cryptochiridae is the only family recognised in Cryptochiroidea , cleary a monophyletic family despite the presence of several subfamilies (Guinot et al., manuscript). It is generally included in Thoracotremata ( Ng, Guinot & Davie 2008). The larval characters contradict such a placement, and a re-evaluation of the adult morphological features leads to a tentative placement as a basal heterotreme eubrachyuran superfamily, such as the Hymenomatoidea (See Guinot 2011b; Position of the Cryptochiroidea and Pinnotheroidea within the Brachyura ; Cephalic condensation).

Figures

FIGURE 58. Male reproductive system in Hymenosomatoidea (A, B, E), Pinnotheroidea (C, D), and male gonopores in Cryptochiroidea (F). A, B, dissection of Odiomaris pilosus (A. Milne-Edwards, 1873), male 11.0 × 14.0 mm, New Caledonia, Wé Waalu River (MNHN-B32604): ejaculatory duct and penis (highlighted in B); C, D, dissection of Dissodactylus crinitichelis Moreira, 1901, male 4.6 × 7.0 mm, Brazil (MZUSP 24231): ejaculatory duct (highlighted in D). E, testis and vas deferens as seen through the transparent carapace of Trigonoplax unguiformis (De Haan, 1839), male 6.1 × 7.3 mm, Western Australia (USNM 184973); F, Utinomiella dimorpha (Henderson, 1906): male gonopores perforating sternite 8 far from suture 7/8 (modified from Henderson 1906: pl. 8, fig. 8, as Cryptochirus dimorphus). cx1, cx5, P1, P5 coxae; e.d., ejaculatory duct; g, gonopore; p, penis; t, testis; 4–8, thoracic sternites 4–8; 4/5–7/8, interrupted thoracic sternal sutures 4/5–7/8. Scale bars: 1 mm (A, B); 4 mm (C, D).