DROMIINAE De Haan, 1833

Guinot, Danièle & Quenette, Gwenaël, 2005, The spermatheca in podotreme crabs (Crustacea, Decapoda, Brachyura, Podotremata) and its phylogenetic implications, Zoosystema 27 (2), pp. 267-342 : 284

Subfamily DROMIINAE De Haan, 1833

The female thoracic sternites 7 and 8 are more or less strongly tilted backwards. In adult females, sternites 7 and 8 grow forward, encroaching the preceding sternites (6, 5, and even 4), and sutures 7/8 advance far forward, sometimes so far that sternites 7 and 8 occupy much of the ventral surface of the cephalothorax ( Fig. 1 ). Additionally, in many dromiids the female sternal surface becomes more complex, owing to the fact that the apertures of the spermathecae often end apart on (or beneath) two more or less prominent tubercules, or more or less together on (or beneath) a unique tubercle ( Forest 1974: fig. 6b, c, pl. 6, figs 1, 2). Dromiine females consequently show a completely distorted thoracic sternum. From the observations and figures given by Gordon (1950: 244, figs 23-25, pl. 1, fig. B, as Dromia vulgaris ) it is clear that the dromiid spermatheca constitutes a differentiated complex structure. The present study expands the results of Guinot & Tavares (2003) and confirms the characters of dromiine spermatheca as a generic one. The axial skeleton of the Dromiinae , figured here for several species ( Figs 7 ; 10B ; 11A ; 12B ), typically shows the following organization: connections between the phragmae effected by fusion; endopleurites of each lateral part remaining on the sides, the two sides being connected by a wide transverse bridge; intertagmal phragma exclusively fused with the endosternal part of the skeleton; and absence of a sella turcica ( Secretan 1998: 1758, figs 9-11). Endosternite 7/8 is completely modified, notably by presence of the spermathecal tube.

Figures

FIG. 1. — Modified thoracic sternum and long sutures 7/8 of the female of an unidentified dromiid (probably Lauridromia sp.) (Dromiidae, Dromiinae) (MNHN) (see Tavares 1994: fig. 37C, D); A, external view, with spermathecal aperture at level of P1; B, internal view, most of interosternites 4/5-7/8 removed, showing internally closed tube. Abbreviations: a, aperture of the spermatheca at extremity of sternal suture 7/8; a.c., arthrodial cavity of P3; i4/5-i7/8, interosternites 4/5-7/8; s, location of the spermathecal pocket or chamber; t, spermathecal tube; 4-8, sternites 4-8; 6/7, 7/8, thoracic sternal sutures 6/7, 7/8. (Courtesy of S. Secretan and M. Tavares).

FIG. 7.— Dromia personata (Linnaeus,1758),female 64.2 × 77.1 mm, France (MNHN-B 21971); A, axial skeleton, dorsoventral view, spermathecae in situ, bulb and chamber visible; B, posterior part enlarged, tube discernible on the bottom. Abbreviations: b, bulb; br, transverse bridge; c, spermathecal chamber; i.p., intertagmal phragma; t, spermathecal tube; 8, sternite 8. (See Secretan 1998: fig. 11). Scale bar: A, 1 cm.

FIG. 10. — [Dromia] wilsoni (Fulton & Grant, 1902), female 35 × 47.8 mm, Marquesas Islands (MNHN-B 26480); A, thoracic sternum; B, axial skeleton, dorsoventral view, spermathecae not visible. Abbreviations:a, spermathecal aperture; br, transverse bridge; cx3, P3 coxa; e4, e5, episternites 4, 5; g, female gonopore; i.p., intertagmal phragma; 4, sternite 4; 7/8, thoracic sternal sutures 7/8. Scale bars: 1 cm.

FIG. 11. — A, Takedromia cristatipes (Sakai, 1969), ovigerous female 19.8 × 21.6 mm, New Caledonia (MNHN-B 26420), axial skeleton; B, Epigodromia areolata (Ihle, 1913), female 12.2 × 13.3 mm, New Caledonia (MNHN-B 26336), thoracic sternum. Abbreviations: a, spermathecal aperture; br, transverse bridge;cx3, P3 coxa; e4, e5, episternites 4, 5; g, female gonopore; i.p., intertagmal phragma; s, spermathecal chamber; 4, 8, sternites 4, 8; 7/8, thoracic sternal suture 7/8. Scale bars: A, 4 mm; B, 1 mm.

FIG. 12. — Frodromia? atypica (Sakai, 1936), ovigerous female 10.6 × 9.9 mm, New Caledonia, McLay det. (MNHN-B 26360); A, thoracic sternum; B, thoracic axial skeleton, with endopleurites cut away at left to expose spermatheca. Abbreviations: a, spermathecal aperture at extremity of sternal suture 7/8; b, bulb; bo, flat bottom of the sterno-abdominal depression; br, transverse bridge; cx1, cx3, P1, P5 coxae; e4, e5, episternites 4, 5; g, female gonopore; i.p., intertagmal phragma; sr, spur on P3 coxa; s8, internal surface of sternite 8; tb, tubular process on P3 coxa; 4, 8, sternites 4, 8; 7/8, thoracic sternal suture 7/8. Scale bars: 1 mm.