PODOTREMATA Guinot, 1977

Guinot, Danièle & Quenette, Gwenaël, 2005, The spermatheca in podotreme crabs (Crustacea, Decapoda, Brachyura, Podotremata) and its phylogenetic implications, Zoosystema 27 (2), pp. 267-342 : 278

Section PODOTREMATA Guinot, 1977

Subsection DROMIACEA De Haan, 1833

In all the Dromiacea the thoracic sternum (sternal plate) forms in both sexes a relatively narrow shield, with all sternites almost completely fused together, except laterally where traces of the sutures are still visible near the condylar articulation of the coxae of the pereopods ( Homolodromiidae : Figs 3A ; 27A ; Dromiidae : Figs 1A ; 5 ; 8A ; 10A ; 11B ; 12A ; 13 ; 15 ; 16A ). The sutures are sometimes so faint that they are hardly apparent ( Dynomenidae : Fig. 4A, C ). The second gonopods are very long, often longer than the first, always each with a needle-like flagellum (except for the enigmatic Stebbingdromia Guinot & Tavares, 2003 ).

A review of the morphology of the Dromiacea, considered monophyletic, had revealed the wealth of morphological patterns found in the Dromiidae ( Guinot & Tavares 2003) . A subfamilial division f o r t h e D r o m i i d a e w i t h t h r e e s u b f a m i l i e s, Dromiinae De Haan, 1833 , Hypoconchinae Guinot & Tavares, 2003 , and Sphaerodromiinae Guinot & Tavares, 2003 , was proposed ( Guinot & Tavares 2003).

The typical spermatheca of an adult dromiacean may be internally subdivided into two or three parts. After dissection, a female specimen Dromia marmorea Forest, 1974 ( Dromiidae Dromiinae) showed three parts ( Figs 2 ; 6 ): 1) at the posterior corner of the endosternite 7/8, a strongly calcified boss, the bulb; 2) a larger structure, a chamber, also named pocket, that corresponds to the main bulge of the endosternite 7/8, its size depending of the space left between the two sheets which form both external (endosternite 7) and inner (endosternite 8) walls; and 3) along the rest of the length of the suture 7/8, a long and calcified hollow tube, with a relatively small lumen, communicating with the exterior (see also Fig. 14 ). This channel is not found in all Dromiacea; it is absent in one dromiid subfamily ( Sphaerodromiinae ), in the Dynomenidae , and in all other Podotremata where the chamber directly communicates with the exterior.

Superfamily HOMOLODROMIOIDEA

Figures

FIG. 3. — Homolodromia kai Guinot, 1993, female 12.4 × 8.3 mm, Indonesia, Kai Islands (MNHN-B 22704); A, thoracic sternum; B, axial skeleton, with spermathecal bulb visible but short spermathecal tube not discernible; C, detail of A, left posterior part; D, detail of B, left posterior part. Abbreviations: a, spermathecal aperture at extremity of sternal suture 7/8; b, bulb; i, connections by interfingering; i.p., intertagmal phragma; 4-8, sternites 4-8; 7/8, thoracic sternal suture 7/8. Scale bars: A, B, 4 mm; C, D, 2 mm.

FIG. 27. — A, Homolodromia bouvieri Doflein, 1904 (Homolodromiidae), ovigerous female 33 × 26 mm, Madagascar (MNHN- B 28940), thoracic sternum (sternites 1-3 not drawn); B, Cryptodromia tuberculata Stimpson, 1858 (Dromiidae), ovigerous female 9 × 10 mm (with large eggs), New Caledonia, Karembé, McLay det. (MNHN-B 26387), spermathecal apertures as long opened slits. Abbreviations: a, spermathecal aperture; cx1-cx5, P1-P5 coxae; e4, e5, episternites 4, 5; g, female gonopore; sl, slit; t, tubercule; 4-8, sternites 4-8; 6/7, 7/8, thoracic sternal sutures 6/7, 7/8. Scale bar: A, 5 mm; B, 2.5 mm.

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. 5. — Thoracic sternum in two species of Dromia Weber, 1795 (Dromiidae, Dromiinae); A, D. personata (Linnaeus, 1758), female 47 × 58 mm, France, Island of Yeu (MNHN); B, D. marmorea Forest, 1974, female paratype 57 × 73 mm, near Dakar (MNHN) (Courtesy of J. Forest). Abbreviations: a, spermathecal aperture at extremity of sternal suture 7/8; cx1-cx3, P1-P3 coxae; e4, e5, episternites 4, 5; g, female gonopore; r, ring encircling spermathecal aperture; 4-8, sternites 4-8; 6/7-7/8, thoracic sternal sutures 6/7 to 7/8.

FIG. 8. — [Dromia] dormia (Linnaeus, 1763), female 107 mm carapace length, New Caledonia (MNHN-B 26439); A, thoracic sternum; B, detailed part view of spermatheca, skeletal parts removed. Abbreviations: b, bulb; b.t., basal thickening; c1, soft part of spermathecal chamber; c2, rigid part of spermathecal chamber; cx3, P3 coxa; e4, e5, episternites 4, 5; g, female gonopore; p, pit; r, ridge between the two pits; 4-8, sternites 4-8; 4/5-7/8, thoracic sternal sutures 4/5 to 7/8. 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.

FIG. 13. — Lauridromia intermedia (Laurie, 1906), female 37.3 × 35.4 mm, New Caledonia (MNHN-B 26441); A, thoracic sternum; B, C, two views of the tubercle bearing spermathecal aperture (notice that the two sheets of the phragma 7/8 are not completely joined in their terminal parts). Abbreviations: a, spermathecal aperture; cx1-cx3, cx5, P1, P2, P3, P5 coxae; g, female gonopore; o.p., opened part of the phragma 7/8; s.p., sperm plug; t, tubercle; 4-8, sternites 4-8; 5/6-7/8, thoracic sternal sutures 5/6 to 7/8. Scale bars: A, C, 2.5 mm; B, 5 mm.

FIG. 15. — Sternodromia spinirostris (Miers, 1881); A, female 40 × 41 mm, Gulf of Guinea (MNHN-B 22052), thoracic sternum showing sperm plug around slits of the spermathecae; B, female 34 × 37.2 mm, Gulf of Guinea (MNHN), detailed view of anterior sternal plate. Abbreviations: a, spermathecal aperture; cx1, cx5, P1, P5 coxae; e5, episternite 5; g, female gonopore; sl, slit; s.p., sperm plug; t, tubercle; 4-8, sternites 4-8; 5/6-7/8, thoracic sternal sutures 5/6 to 7/8. Scale bar: A, 2.5 mm.

FIG. 16. — Hypoconcha panamensis Smith, 1869, female approximately 30 mm width, Mexico, Cabo San Miguel (MNHN-B 20865); A, thoracic sternum; B, detail of posterior part; C, axial skeleton, not dissected so that spermathecae are not visible. Abbreviations: a, spermathecal aperture; br, transverse bridge; c, crest surrounding spermathecal aperture; cx1, cx3, P1, P3 coxae; e4, e5, episternites 4, 5; g, female gonopore; i.p., intertagmal phragma; m, membranous zone separating the flat anterior sternal part from tilted last sternites; 4, 8, sternites 4, 8; 7/8, thoracic sternal suture 7/8. Scale bars: A, C, 4 mm.

FIG. 4. — A, B, Metadynomene tanensis (Yokoya, 1933), female 20.5 × 21.9 mm, New Caledonia (MNHN-B 26576); C, D, Dynomene pilumnoides Alcock, 1900, female 12.4 × 14.5 mm, Madagascar (MNHN-B 6913); A, C, thoracic sternum; B, D, axial skeleton, with connections by fusion. Abbreviations: a, spermathecal aperture at extremity of sternal suture 7/8; br, transverse bridge; cx3, P3 coxae; g, female gonopore; i.p., intertagmal phragma; 1-3, sternites 1-3; 4-8, sternites 4-8; 7/8, thoracic sternal suture 7/8. Scale bars: 5 mm.

FIG. 2. — The three main internal parts of a typical dromiacean spermatheca, after the removal of the skeleton, median view, Dromia marmorea Forest, 1974 (Dromiidae, Dromiinae), female 57 × 72 mm, Azores (MNHN-B 21900). Abbreviations: a, communication with exterior by spermathecal aperture; b, bulb; c, chamber; t, spermathecal tube. Scale bar: 0.5 cm.

FIG. 6. — Details of the spermatheca of Dromia marmorea Forest, 1974 (Dromiidae, Dromiinae), female 57 × 72 mm, Azores (MNHN- B 21900); A, posterior part of axial skeleton in median view to show spermatheca in situ; B, details of foldings at level of the spermathecal bulb; C, lateral view, skeletal parts removed; D, vertical view of spermathecal chamber, cut to show sperm inside. Abbreviations: a, communication of the spermatheca with exterior; b, bulb; c, chamber, uneven surface of inner wall; e5, episternite 5; en 6/7, endopleurite 6/7; is 6/7, interosternite 6/7; t, spermathecal tube. Scale bars: A, C, 1 cm.

FIG. 14. — Lauridromia dehaani (Rathbun, 1923), female 52 mm length, Madagascar (MNHN-B 6868), spermatheca in lateral view, skeletal parts removed. Abbreviations: a, location of the spermathecal aperture on sternum; b, bulb; b.t., basal thickening; c, spermathecal chamber; s8, internal surface of sternite 8; t, spermathecal tube. Scale bar: 1 mm.