Speocarcinus Stimpson

Brandão, Marianna, Coelho-Filho, Petronio Alves & Tavares, Marcos, 2012, A review of the genus Speocarcinus Stimpson, 1859 (Crustacea: Brachyura: Xanthidae), with a key to its species and the description of one new species, Zootaxa 3327, pp. 1-19 : 17

Key to the species of Speocarcinus Stimpson

1. Dorsal median tubercle on male and female abdominal segment 2............................... S. monotuberculatus

- No dorsal median tubercle on abdominal segment 2......................................................... 2

2. Tooth on inner margin of P1 carpus remarkably strong........................................................ 3

- Tooth on inner margin of P1 carpus short, blunt............................................................ 4

3. P1 propodus with longitudinal row of granules across dorsal and ventral margins; propodus lateral surface microscopically granular, coarsely granular posteriorly. Dorsal surface of P1 carpus evenly coarsely granular............. S. granulimanus

- P1 propodus generally smooth, except for row of granules along proximal part of its inferior margin. Dorsal surface of P1 carpus smooth, except for small granules lining margins and scattered, minute granules near inner margin...... S. spinicarpus

4. Distal end of G1 bent in the form of an inward curve and again towards the interior of sterno-abdominal cavity ( Fig. 7A, B ). Vulva obliquely oriented in relation to median line of thoracic sternum ( Fig. 8A ). Frontal region behind frontal margin of carapace smooth.......................................................................................... 5

- Distal end of G1 bent only in the form of an inward curve. Vulva transversely oriented in relation to median line of thoracic sternum. Frontal region behind frontal margin of carapace coarsely granular transversely............................ 6

5. Pterygostomian region with one distinct transverse row of coarse granules above inhalant channel. Frontal margin finely granular. Thoracic sternum slightly punctate......................................................... S. amazonicus

- Pterygostomian region densely granular above inhalant channel, no distinct transversal row of granules. Frontal margin smooth. Thoracic sternum microscopically granular.................................................... S. meloi

6. Ocular peduncle distinctly granular. Male abdominal segment 2 partially intercalated between edges of abdominal segments 3–5................................................................................................. 7

- Ocular peduncle smooth. Male abdominal segment 2 free, not intercalated between edges of abdominal segments 3–5............................................................................................... S. carolinensis

7. Branchiostegal region with one transversal row of granules, no granules above and immediately below that row. A narrow gap between anterolateral teeth 3 and 4 and 4 and 5 (last anterolateral tooth); anterolateral teeth 1–4 lobate, fifth tooth short, truncate........................................................................................ S. lobatus

- Branchiostegal region densely granular above and below the transversal row of granules. A wide gap between anterolateral teeth 3 and 4 and 4 and 5 (last anterolateral tooth); anterolateral teeth 1–3 lobate, fourth and fifth strong, spiniform................................................................................................ S. dentatus n. sp.

Figures

FIGURE 7. A – G, First male gonopods (B, D, G, detail of the distal end). A – B, Speocarcinus amazonicus Brandão, Tavares & Coelho-Filho, 2010, holotype male cl 8 mm, cw 11 mm (MZUSP 23654). C – D, Speocarcinus dentatus n. sp., male holotype cl 11.5 mm, cw 22.5 mm (MZUSP 12615). E, Speocarcinus lobatus Guinot, 1969, male cl 5 mm, cw 10 mm (USNM 187170). F – G, Speocarcinus spinicarpus Guinot, 1969, male cl 7 mm, cw 14 mm (USNM 127056). Scale bars: A, C, E – F, 2 mm; B, D, G, 1 mm.

FIGURE 8. A – D, Female thoracic sternum (abdomen not represented). A, Speocarcinus amazonicus Brandão, Tavares & Coelho-Filho, 2010, cl 7 mm, cw 10 mm (MZUSP 23655). B, Speocarcinus carolinensis Stimpson, 1859, cl 6 mm, cw 9 mm (USNM 180100). C, Speocarcinus dentatus n. sp., cl 4 mm, cw 7 mm (MZUSP 12628). D, Speocarcinus spinicarpus Guinot, 1969, cl 7 mm, cw 14 mm (USNM 127056). Note in A the female gonopore obliquely oriented in relation to median line of thoracic sternum. Scale bars: A – B, 2.5 mm; C – D, 2 mm.