Strobiligera santista, Fernandes & Pimenta, 2019

Fernandes, Maurício Romulo & Pimenta, Alexandre Dias, 2019, Taxonomic review of Inella and Strobiligera (Gastropoda: Triphoridae) from Brazil, Zootaxa 4613 (1), pp. 1-52 : 40-43

Strobiligera santista sp. nov.

Figure 24

urn:lsid:zoobank.org:act:68B24A96-B28A-46FC-A366-F4D5C888FB4B

Type material. Holotype: MZSP 32618 . Paratypes: Brazil: São Paulo state: MNRJ 29382 , PADCT sta. 6573 [2]; MNRJ 29374 , REVIZEE-Sul sta. 6676 [1]; MNRJ 32917 , 25 º 13ʹ 0 6ʺ S, 44º 59ʹ 31ʺ W, 160 m, viii/2008 [1].

Description. Shell sinistral, elongated, conical-fusiform, rectilinear profile, reaching 13.89 mm in length, 2.09 mm in width, length/width ratio 6.6. Protoconch globose, inflated, 0.63–0.78 mm in length, 0.45–0.56 mm in width of its first whorl, 0.49–0.58 mm in width of its last whorl; 2.75 convex whorls, clear distinction between protoconch and teleoconch; initial 1.5 whorl dome-shaped, broad, smooth; remaining 1.25 whorl with two main spiral cords, situated at 34–44% and 61–69% of whorl height, the abapical one slightly more pronounced; minute, very faint, axial marks across the entire whorl length. Teleoconch with up to 20 whorls; three spiral cords in the beginning, the median and abapical cords continuous with those of the protoconch; adapical cord narrower than other cords through most of teleoconch, but slowly strengthening and acquiring the same size of the abapical one (the median cord is more pronounced than others in mid-late whorls) only on the body whorl, in which the distance between spiral cords is 1.2 times the width of cords; 14 to 15 orthocline to slightly opisthocline axial ribs; rounded nodules of a medium size; well-developed suture, with a distinct sutural cord; moderately thick, smooth subperipheral cord, only one smooth, thin basal cord; no supranumerical cords; elliptical aperture, 1.35 mm long, 0.99 mm wide, ratio length/width 1.4; posterior and anterior canals not fully formed, with the latter being directed downwards. Light brown protoconch (first whorl usually translucent white), cream teleoconch, with nodules clearer than internodular spaces in the spiral cords.

Remarks. Strobiligera santista sp. nov. is similar to Strobiligera campista sp. nov. both in teleoconch and protoconch sculpture, in addition to shell coloration. Their main differences comprise the nearly fusiform and thin shell shape of Strobiligera santista sp. nov. (more conical and broader in Strobiligera campista sp. nov.), the more gradual strengthening of the adapical spiral cord and presence of smaller nodules of teleoconch (making internodular spaces more evident in Strobiligera santista sp. nov.), the number of basal cords (one in Strobiligera santista sp. nov., three in Strobiligera campista sp. nov.), and the slightly larger dimensions of the protoconch in Strobiligera santista sp. nov. Preserved shells of Strobiligera campista sp. nov. are recorded as deep as ~ 150 m and are apparently restricted to the Campos Basin, thus showing a shallower and more northerly distribution than Strobiligera santista sp. nov., which is apparently restricted to the Santos Basin, between 153 m and 258 m.

Strobiligera santista sp. nov. is distinguished from S. dinea by shell color (mainly cream teleoconch and light brown protoconch, instead of the white shell of S. dinea ) and by having reduced dimensions of the protoconch, which is much inflated in S. dinea . Strobiligera santista sp. nov. also inhabits the transition between the continental shelf and slope (153 m to 258 m), contrary to the strictly bathyal records of S. dinea (607 m to 940 m).

Geographical distribution. Brazil: São Paulo.

Bathymetric distribution. 153–258 m.

Figures

FIGURE 24. Strobiligera santista sp. nov. A. MZSP 32618, holotype, 13.89 mm. B–E, holotype. F. MNRJ 29382, paratype, 8.66 mm. G. MNRJ 29374, paratype, 6.71 mm. H: same shell as F. I: same shell as G. J, shell not illustrated. Scale bars:A, C–G, 1 mm; B, 500 µm; H–I, 200 µm; J, 100 µm.