Philobrya delli Urcola & Zelaya 2024, n. sp.

• Main Authors: Urcola, Matias Ricardo, Zelaya, Diego Gabriel
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2024
• Subjects: Biodiversity; Taxonomy; Animalia; Mollusca; Bivalvia; Arcida; Philobryidae; Philobrya; Philobrya delli; Antarc*; Antarctic
• Online Access: https://doi.org/10.5281/zenodo.10984639

Philobrya delli n. sp. (Figure 10) Philobrya capillata. Dell, 1964: 170 (in part), fig. 2.8, pl. 4, fig. 9 [not text figs. 2.5, 2.9, pl. 4, figs. 4, 5 = P. capillata ]. Type locality: Isla de los Estados, 54°50.96’S 63°52.01’W, 330 m. Type material: Holotype (MACN-In 44440) and five paratypes from the type locality (4 paratypes MACN-In 44441; 1 paratype MLP-Ma 16118). Zoobank registration number: 01B0FCD6-0233-493C-A723-9123E433C416. Other material examined: Burdwood Bank: 53°51.50’S 61°51.50’W, 368‒463 m (NHMUK 1962868: 2 v); 54°23.82’S 58°30.53’W, 135 m (MACN-In 44442: 2 v). Distribution: Isla de los Estados and Burdwood Bank; 135‒ 463 m. Etymology: The species is named after Richard Kenneth (“Dick”) Dell (1920–2002), in recognition for his first input to the knowledge of sub-Antarctic and Antarctic philobryids. Diagnosis: Shell mytiliform, delicate, with the anterior portion of dorsal margin short. Dissoconch sculptured with 20‒24 strong radial ribs. Inner shell surface and margins strongly crenulated. Resilifer narrow, elongate. Description: Shell large (maximum L = 9.6 mm), mytiliform, relatively high ( H/L = 0.84 ± 0.03, n = 3), inflated (W/H = 0.80 ± 0.08, n = 3), delicate; with a narrow, ill-defined dorsal slope. Umbos broad, well-outstanding from shell outline, located at anterior end. Umbonal angle: 90‒100° (n = 6). Dorsal margin with the anterior portion short, straight, vertical, and the posterior portion arched, forming a continuous curve with the posterior margin. Ventral margin slightly sinuated by byssal notch. Prodissoconch D-shaped, with posterior end higher than anterior end, widely projected ventrally, of 625‒650 µm Lp (n = 6), separated from the dissoconch by a prominent rim. Antero-dorsal and postero-dorsal areas raised, sculptured with prominent commarginal folds. Central area with radial sculpture (but badly preserved in the available material). Dissoconch whitish, dull. Sculpture consisting of 20‒24 strong radial ribs and irregular but well-marked growth lines. Periostracum unknown ...