Notocrater christofferseni
- Dataset
- Notocrater christofferseni n. sp. (Vetigastropoda: Pseudococculinidae): first record of the genus in the South Atlantic Ocean
- Rank
- SPECIES
- Published in
- Lima, Silvio Felipe Barbosa (2014): Notocrater christofferseni n. sp. (Vetigastropoda: Pseudococculinidae): first record of the genus in the South Atlantic Ocean. Zootaxa 3873 (2): 178-186, DOI: 10.11646/zootaxa.3873.2.5
Classification
- kingdom
- Animalia
- phylum
- Mollusca
- class
- Gastropoda
- order
- Lepetellida
- family
- Pseudococculinidae
- genus
- Notocrater
- species
- Notocrater christofferseni
description
Description. Shell small (SL: 2.81 mm; SP: 1.42 mm; SW: 2.01 mm; SH: 1.45 mm); opaque white, rather thin. Outline in dorsal and ventral view broadly elliptical (Figs 2 B, 3 C), highly arched (SH / SL = 0.51), anterior region occupying about 95 % of shell length (AP: 2.66 mm) (Fig. 2 A – B). Summit flattened, posterior of center (SP / SL = 0.50) (Fig. 2 A – B). Protoconch (PL: 205 µm; PW: 92.67 µm) well below apex, well posterior to center (AP / SL = 0.95) vertically near posterior margin of teleoconch (Figs 1 A, 2 A), showing a smooth surface; it is not clear whether tiny pits / holes and minute, sparse crystals on surface are in living shell or are post-mortem bioerosion or adhesions / artifacts (respectively); apical fold and suture not clearly discernible due to presence of concretions (apical fold apparently long, narrow); posterior margin embedded in posterior slope of teleoconch (Fig. 3 A – B). Teleoconch at first sculptured with fine, rather crisp and irregularly spaced concentric riblets (Fig. 2 C – D); following shell length of about 2.2 to 2.4 mm, riblets become irregular (slightly anastomosed) (Fig. 2 E), then interrupted into roughly oval to elliptical, strong, rather regularly spaced pustules (rarely quadrate or hemispherical) (Fig. 2 F), that align to form about 50 concentrically arranged (regularly curved) rows; pustules most prominent at shell periphery (Fig. 2 A – B, F); very fine striae grouped concentrically between pustules; sparse, tiny, irregularly scattered pits / holes on and between pustules (Fig. 2 F); it is not clear whether pits / holes are in living shell or are post-mortem bioerosion. Radial striae or threads not observed on shell. Anterior slope broad, weakly convex (Fig. 2 A – B). Anterior end broadly rounded (Fig. 2 B). Posterior slope very steep, weakly concave (Fig. 2 A). Posterior end rounded, narrower anterior end (Fig. 2 B). Lateral slopes nearly flattened, straight, parallel (Fig. 2 B). Aperture broadly elliptical in ventral view (Figs 1 B, 3 C), not planar, shallowly concave in lateral view (Figs 1 A, 2 A). Shell edge rather thin, crisp (Figs 1 A, 2 A, 3 C). Inner surface polished, except for barely distinguishable muscle scars (Fig. 3 C).
diagnosis
Diagnosis. Shell highly arched (SH / SL = 0.51). Summit flattened, posterior of center (SP / SL = 0.50). Protoconch well below apex, vertically near posterior extremity. Anterior region occupying about 95 % of shell length. Posterior slope very steep, weakly concave. Teleoconch at first sculptured with concentric riblets, following shell length of about 2.2 to 2.4 mm, riblets become irregular, then interrupted into roughly oval to elliptical pustules aligned to form about 50 concentrically arranged (regularly curved) rows from anterior margin to center of shell. Striae very fine between pustules.
etymology
Etymology. The species described herein is named in homage to Prof. Dr. Martin Lindsey Christoffersen (Department of Systematics and Ecology, Federal University of Paraíba, Brazil) who has dedicated three decades to the teaching of zoology and the training of masters and doctors of biological science (taxonomists and systematists), with emphasis on the phylogenetic systematics of marine invertebrates. Comparison. Notocrater christofferseni n. sp., N. houbricki and N. youngi are similar in having a shell with a broadly elliptical outline in the dorsal and ventral views, rounded anterior and posterior ends, a weakly convex anterior slope, nearly flattened lateral slopes with a thin edge and flattened summit which is situated posterior to the center. Furthermore, these species have protoconchs with the posterior margin embedded in the posterior slope of the teleoconch. There are a number of conchological differences between Notocrater christofferseni n. sp. and N. youngi. The new species has a more elongated protoconch (205 µm), well below the apex and well posterior to the center (AP / SL = 0.95), with a smooth surface, a highly arched shell (SH / SL = 0.51) with the anterior region occupying about 95 % of shell length (AP: 2.66 mm), the surface sculptured with prominent pustules (no radial striae or threads) and a very steep and convex posterior slope. In contrast, McLean & Harasewych (1995: 26, figs. 66 – 69) and Ardila & Harasewych (2005: 359, fig. 12) characterized N. youngi as having a protoconch measuring 190 µm in length, barely below the apex and posterior to the center (AP / SL = 0.64) sculptured with clumped crystals, some forming anastomosing threads, a moderately arched shell (SH / SL = 0.32 to 0.42), an anterior region occupying about 60 % of shell length, a surface sculptured with slight pustules and a very fine radial threads and moderately inclined, straight posterior slope.
materials_examined
Type material. Holotype — MNRJ 26704: Brazil: northeastearn Brazil: off the state of Alagoas, 10 ° 06 ' 35 '' S, 35 ° 46 ' 41 '' W, 720 m, 16. xii. 2001, ‘ Natureza’ collector. Type locality. Off the state of Alagoas (northeastearn Brazil: 10 ° 06 ' 35 '' S, 35 ° 46 ' 41 '' W), 720 m depth. Geographic distribution. Known only from the type locality.
Name
- Homonyms
- Notocrater christofferseni