Sagenotriphora sp. 2, Marshall, 1983

Fernandes, Maurício Romulo & Pimenta, Alexandre Dias, 2020, Unraveling one of the ‘ Big Five’: update of the taxonomy of Triphoridae (Gastropoda, Triphoroidea) from Brazil, European Journal of Taxonomy 665 (665), pp. 1-170 : 36-38

Sagenotriphora sp. 2

Figs 16 , 24E , 64

Material examined

BRAZIL – Rio de Janeiro • 1 spec.; REVIZEE-Central C1-D3; IBUFRJ 19556 .

Description

Shell sinistral, elongated, cyrtoconoid, slightly convex profile, 3.1 mm long, 1.1 mm wide, length/width ratio 2.8. Protoconch multispiral, conical, 4.5 convex whorls, 0.48 mm long, 0.36 mm wide; embryonic shell dome-shaped, covered by irregular-shaped granules, vesicular granules appearing in final and abapical portion of embryonic shell, resulting in axial ribs of larval shell; larval shell with two spiral cords, situated at ~27% and ~58% of last whorl height; 33 nearly rectilinear to slightly sigmoid axial ribs. Teleoconch with seven whorls; two spiral cords, abapical one continuous to that of protoconch, median spiral cord absent; spiral cords initially with same strength, abapical cord becomes broader betwen beginning of fourth and end of fifth whorls, but adapical cord becomes most developed in following whorls; on body whorl, spiral cords are 1.4 × as wide as distance between them; weak axial ribs, irregularly disposed, orthocline to slightly opisthocline; rounded and very close nodules (with reduced internodular spaces), with medium to large size, according to thickness of spiral cord; welldeveloped and spaced suture, with strong and wavy sutural cord; subperipheral and two basal cords spaced and wavy, sometimes developing minute nodules, especially in subperipheral cord; two very small supranumerical cords appear near peristome, one between adapical and abapical spiral cords, other between abapical and subperipheral cords; elliptical aperture, 0.62 mm long, 0.41 mm wide, length/ width ratio 1.5; totally open anterior canal, curved downwards, 0.20 mm long, 0.22 wide, length/width ratio 0.9; posterior canal is deep notch, 0.17 mm long, not detached from aperture. Beige teleoconch, light brown protoconch, darker than teleoconch.

Remarks

The protoconch of Sagenotriphora sp. 2 is very similar to that of S. osclausum , with the embryonic shell possessing vesicular granules ( Fig. 16G ) and the larval shell with two median spiral cords of equal strength ( Fig. 16F ), in addition to a similar shell color. Their main differences comprise Sagenotriphora sp. 2 not developing a median spiral cord until the end of the seventh whorl of teleoconch (whereas such cord emerges in the fourth or fifth whorl in S. osclausum ), but showing a change of thickness of spiral cords throughout the teleoconch ( Fig. 16 B–C) (whereas cords with nearly the same thickness in S. osclausum ). In addition, Sagenotriphora sp. 2 has a considerable development of the suture and very reduced internodular spaces in spiral cords of teleoconch (internodular spaces more developed in S. osclausum ). This species is tentatively placed in Sagenotriphora solely due to its resemblance with S. osclausum .

Geographical records

Brazil: Rio de Janeiro.

Bathymetric distribution

Only known from 80 m depth.

Figures

Fig. 16. Sagenotriphora sp. 2. A–G. IBUFRJ 19556, 3.09 mm. Scale bars: A–C = 1 mm; D–E = 500 µm; F = 100 µm; G = 50 µm.

Fig. 24. Triphoridae from Brazil (3). A. Nototriphora decorata (C.B. Adams, 1850). B. Sagenotriphora albocaput sp. nov. C. Sagenotriphora osclausum (Rolán & Fernández-Garcés, 1995). D. Sagenotriphora sp. 1. E. Sagenotriphora sp. 2. F. Similiphora intermedia (C.B. Adams, 1850). G. Similiphora lucida sp. nov. H. Similiphora sp. 1. I. Strobiligera campista Fernandes & Pimenta, 2019. J. Strobiligera delicata Fernandes & Pimenta, 2014. K. Strobiligera dinea (Dall, 1927). L. Strobiligera gaesona (Dall, 1927). M. Strobiligera inaudita (Rolán & Lee, 2008). N. Strobiligera santista Fernandes & Pimenta, 2019. O. Strobiligera unicornium (Simone, 2006). P. Strobiligera sp. 1. Q. Strobiligera sp. 2. R. Triphora atlantica Smith, 1890. S. Triphora charybdis Fernandes & Pimenta, 2015. T. Triphora ellyae De Jong & Coomans, 1988. U. Triphora elvirae De Jong & Coomans, 1988. V. Triphora portoricensis Rolán & Redfern, 2008. W. Triphora scylla Fernandes & Pimenta, 2015. Scale bars: 1 mm.

Fig. 64. Distribution map of Sagenotriphora albocaput sp. nov. (red circle = type locality; black circles = additional localities) and Sagenotriphora sp. 2 (gray circle).