Tichosina plicata Cooper, 1977

Rojas, Alexis, Gracia, Adriana & Patarroyo, Pedro, 2015, Brachiopods from off the San Bernardo Archipelago (Colombian Caribbean), with comments on specific synonymies in Tichosina Cooper, 1977, Zootaxa 3914 (1), pp. 55-63 : 57

Tichosina plicata Cooper, 1977

( Fig. 2 A–E)

1977 Tichosina bullisi Cooper , p. 66–67, pl. 6, figs 1–8.

1977 Tichosina dubia Cooper , p. 68–69, pl. 12, fig. 18; pl. 19, figs 2–7; pl. 21, figs 1–5. 1977 Tichosina plicata Cooper , p. 82–83, pl. 5, figs 9–15; pl. 21, figs 6–11. v2009 Tichosina sp. indet.—Rojas et al., figs. 2a–c.

Occurrence. Off the San Bernardo Archipelago, Colombian Caribbean: MARCORAL stations D3 (N 9° 48.88'; W 76° 12.47'), D12 (N 9° 47.10'; W 76° 13.28'), D28 (N 9° 46.64'; W 76° 13.86'). MACROFAUNA II stations E–155 (9° 47' 12" N; 76° 13' 45" W) and E–156 (9° 47' 0.9" N; 76° 14' 12" W) from Reyes et al. (2005).

Material. Two conjoined shells INV BRA 5, INV BRA 6. A total of 33 conjoined shells are available.

Description. External characters: shell large (maximum observed length 36.2 mm), rounded-pentagonal in outline, longer than wide, gently ventribiconvex, maximum width anterior to midlength; beak suberect, foramen moderate in size, labiate, permesothyrid; anterior commissure strongly uniplicate, lateral commissure nearly straight, folding develops in juvenile growth stages; numerous growth lines concentrated toward anterior and anterolateral margins. Internal characters: dorsal valve with cardinal process elliptical, outer hinge plates moderately long, wide, deeply concave; crural bases flat, elevated; crural processes flat, curved inward, bluntly pointed; loop short (<25% of dorsal valve length), wide (20% of dorsal valve width), transverse band wide, broad, slightly arched.

Remarks. The available material is similar in both internal and external characteristics with those for the species T. plicata in Cooper (1977), however, the Colombian specimens are slightly larger. The studied material is similar to Cooper’s illustrations (pl. 5, figs. 9–15; pl. 21, figs. 6–11). Tichosina plicata has been recorded in the southeastern Caribbean (e.g. Venezuela, Trinidad) and the northeastern Atlantic coast of South America ( Logan 1990). Cooper (1977) erected seventeen species of the genus Tichosina from the modern Caribbean Sea. Two of the Cooper’s species, i.e. T. bullisi and T. dubia , show the same general characteristics as T. plicata , and therefore were synonymized. The material studied in the present study consisted of empty and complete (soft bodied) specimens.

Figures

FIGURE 2. Brachiopods off the San Bernardo Archipelago, Colombian Caribbean. A – E. Tichosina plicata Cooper, 1977. A – D. INV BRA 5 conjoined shell. A. Dorsal view. B. Lateral view. C. Ventral view. D. Anterior view. E. INV BRA 6, inner view of dorsal valve showing the loop and broad transverse band. 2 F – I. Terebratulina latifrons Dall, 1920. INV BRA 8 conjoined shell. F. Dorsal view. G. Lateral view. H. Ventral view. I. Anterior view. 2 J – K. Terebratulina cailleti Crosse, 1865. INV BRA 9. J. Inner view of ventral valve. K. Inner view of dorsal valve showing the loop. L – Q. Argyrotheca barrettiana (Davidson, 1866). INV BRA 7. L. Conjoined shell, dorsal view. M. Lateral view. N. Ventral view. O. Anterior view. P. Oblique inner view of ventral valve showing the depressions near to the anterior end of the ventral septum. Q. Inner view of dorsal valve. P – Q. SEM photographs. All scales 5 mm.