Caecum striatum de Folin, 1868

Egger, Christina, Neusser, Timea P., Norenburg, Jon, Leasi, Francesca, Buge, Barbara, Vannozzi, Angelo, Cunha, Regina L., Cox, Cymon J. & Joerger, Katharina M., 2020, Uncovering the shell game with barcodes: diversity of meiofaunal Caecidae snails (Truncatelloidea, Caenogastropoda) from Central America, ZooKeys 968, pp. 1-42 : 1

Caecum striatum de Folin, 1868

Caecum striatum de Folin, 1868 in De Folin and Périer (1867-1871): 49, pl. 5, fig. 3 (with variety obsoleta de Folin, 1874). Type locality: Baie de Bahia [Bahia Bay, Brazil].

Material examined.

Belize • 1; Carrie Bow Cay; 16.8024, -88.0776; depth 19 m; 25 Jan 2010; USNM Belize2010 exped.; Stat. CBC24; DNA voucher; GenBank: MT727061, MT704275; USNM 1618845. • 1 (Fig. 6N-Q ); same collection data as for preceding; ZSM-Mol-20100322.

Shell morphology.

Shell translucent with mottled ochre and white marbling (Fig. 6N ). Size 1.5 mm in length and 0.3 mm in width with thick shell (= 10 µm at aperture). Tube curved regularly with equal width at posterior and anterior end. Blistered, dome-shaped septum with prominent ring separating tube from septum (Fig. 6P ). Mucro central, flat and rounded, pointing slightly dorsal, hardly separated from septum. Aperture simple, straight. Sculpture not visible under the light microscope, i.e., shell appears rather smooth despite two faint transversal rings slightly noticeable close to aperture. SEM examination reveals longitudinal and slightly wavy structure (Fig. 6Q ).

Remarks.

Caecum striatum was identified based on a comparison with the material collected in the sampling region and dedicated as lectotypes by Absalão and Gomes (2001). Their microsculptural description of the type material does correspond to the longitudinal striation of our investigated specimen. Furthermore, shape, mucro, and the noticeably sharp aperture are identical to our specimen. A comparison with a specimen of C. striatum pictured by Pastorino and Chiesa (2014: figs 10-16), also shows the same fine-lined microsculpture as our specimen. Type specimens of three highly similar species, namely C. johnsoni Winkley, 1809, C. antillarum Carpenter, 1858 and C. strigosum de Folin, 1867, are described from Central American waters. Differences can be compared in the reinvestigation of Absalão and Gomes (2001: 20, figs 39-41, 12, figs 11, 12 and figs 7, 8 respectively).

Figures

Figure 6. A-E Caecum heptagonum A specimen USNM 1618866 juvenile specimen with larval shell still attached B-E specimen ZSM-Mol- 20200030, juvenile specimen already resembling closely the adult form B light microscopic picture C SEM scan D close-up of mucro and E microsculpture F-I C. cooperi, specimen MNHN-IM- 2019 - 32 F light microscopic picture G SEM scan H close-up of mucro and I microsculpture whole specimen and close-up of mucro and microsculpture J-M C. debile, specimen MNHN-IM- 2019 - 27 J light microscopic picture K SEM scan L close-up of mucro and M microsculpture N-Q C. striatum, specimen ZSM-Mol- 20100322 N light microscopic picture O SEM scan P close-up of mucro and Q microsculpture R-U C. clathratum, specimen MNHN-IM- 2019 - 17 R light microscopic picture S SEM scan T close-up of mucro and U microsculpture. Scale bars: 10 µm (D, E, I, Q); 20 µm (H, M, P, U); 100 µm (A, B, C, L, N, O, T); 200 µm (F, G, J, K whole specimen); 300 µm (R, S).