Turbonilla obsoleta Dall, 1892

Pimenta, Alexandre D. & Absalão, Ricardo S., 2002, On the taxonomy of Turbonilla puncta (C. B. Adams, 1850) (Gastropoda, Pyramidellidae), with the description of a new species from Brazil and remarks on other western atlantic species, Zootaxa 78, pp. 1-16 : 8-10

Turbonilla obsoleta Dall, 1892 ( Figs. 18­26 )

Turbonilla puncta C. B. Adams, 1850 , var. obsoleta Dall, 1892: 256 ; Odé (1996: 51).

Type locality: Caloosahatchee River, Florida.

Type material: Holotype: USNM 113233. Caloosahatchee River, Florida.

Material examined: The holotype and: ­­Pará State: IBUFRJ 10353, AMASSEDS # 3210 (01°52.45’ N / 16,02’ W, 47 m), 12/v/1990, RVCI coll. [5]; MORG 38640, off Salinópolis (27 m), 26/iv/1968, NOAS coll. [2]; ­­Maranhão State: MNHN, Praia da Raposa [2];.­­Pernambuco State: MNHN, Praia do Despacho [4]; MNHN, Praia da Conceição [1]; MNHN, laguna de Suape, Cabo [5]; MNHN, Praia de Maria Farinha [1]; MNHN, off Recife [4]; MNHN, Praia do Despacho, Itaparica [5]; MNHN, laguna de Suape, Cabo [1]; ­­Bahia State: MORG 23912, Abrolhos bank, i/1985, MORG team coll. [3]; ­­Rio de Janeiro State; IBUFRJ 3151, Prainha, Arraial do Cabo, 1989, T.Almeida coll. [2]; IBUFRJ 10348, Cabo Frio VII # 6147 (22°53.7’S, 041°50.5’W, 50 m), 24/iii/1983, NOAS coll. [1]; IBUFRJ 10347, Prainha, Arraial do Cabo, 1989, T.Almeida coll. [2].

Remarks: Although originally described as a variety of T. puncta , Turbonilla obsoleta Dall, 1892 (figs. 18­26) should be considered a valid species. Dall (1892) distinguished T. obsoleta from T. puncta by the "... feebleness of the spiral sculpture, and especially in the fact that the ribs are not cut abruptly at the periphery... of the last whorl, so that the foveolate character of the interspaces is lost...". However, T. obsoleta has spiral striae more irregularly spaced (fig. 24) than T. puncta . Also, the spiral striae in the base of T. obsoleta (fig. 24) are wider then those in the base of T. puncta . Dall (1892) stated that the degree of expression of the ribs in the base is not constant. We also noted the same variation in specimens of the two species. In T. puncta , there can be obsolete ribs insinuating on the base (fig. 7­8, 10, 12), but they are feeble and do not reach the umbilical region. In T. obsoleta , the ribs do continue through the base (fig. 24), reaching the umbilical region in those specimens with a greater number of whorls (not the case of the holotype (fig. 18)). Moreover, T. obsoleta has a larger protoconch diameter, ranging from 269 m to 340 m (mean diameter: 306, n = 13).

Turbonilla obsoleta has great deal of variation in the general teleoconch shape, which varies from slightly shouldered to a more rectilinear outline (figs. 18­22). Some of the specimens collected along the coast of Pernambuco State (Northeast of Brazil) are very similar in sculpture to T. obsoleta , but differ in the shell shape, as it is more pupoid (figs. 23, 26).

Figures

FIGURES 18 ­ 26: Turbonilla obsoleta Dall, 1892: 18 ­ holotype (USNM 113233), length: 4.5 mm; 19 ­ whole shell (MORG 38640), length: 4.4 mm; 20 ­ whole shell (MNHN), length: 4.6 mm; 21 ­ whole shell (MORG 23912), length: 5.4 mm; 22 ­ whole shell (MORG 38640); 23 ­ whole shell (MNHN), length: 4.7 mm; 24 ­ base (MORG 38640); 25 ­ protoconch (MNHN); 26: base (MNHN). Scale bars: 300 m.