Hiatella umbonata Zelaya and Marina Güller 2023, sp.nov.

• Main Authors: Zelaya, Diego G., Güller, Marina
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2023
• Subjects: Biodiversity; Taxonomy; Animalia; Mollusca; Bivalvia; Adapedonta; Hiatellidae; Hiatella; Hiatella umbonata; Antarc*; Antarctica
• Online Access: https://doi.org/10.5281/zenodo.10474100; http://treatment.plazi.org/id/03E587A0FFCEFFDCFEE5FABBDB7CFBD8

Hiatella umbonata sp.nov. (Figs 3M–O, 6C, D, H, K, 7A–E, 8, 9) Zoobank LSID: urn:lsid:zoobank.org:act: 7E5C1E17-9183- 4BE1-8618-37FDC8B1C421 Saxicava arctica var. antarctica : Melvill and Standen 1907: 151 (in part) (not Philippi, 1845). Hiatella solida : Branch et al. 1991: 47, 51 (not Saxicava solida Sowerby I, 1834). Hiatella sp: Zelaya 2005: 117. Hiatella meridionalis : Simone and Penchaszadeh 2008: 119–127 (not fig. 18); Schejter et al. 2010: 63–67 (not Saxicava meriodionalis d’Orbigny, 1846). Hiatella O: Güller et al. 2020: 143, fig. 3. Type locality: 54°44 ʹ 49″ S, 59°56 ʹ 51″ W, Marine Protected Area Namuncurá I, Burdwood Bank, 177 m depth, B.O. Puerto Deseado , April 2016. Type material: Holotype ( MACN-In 44195 : H9) and one paratype (MACN-In 44196: H10) from the type locality. Etymology: The name derives from the peculiar umbo of this species. Additional material examined: 94 lots (Supporting Information, ESM 1). Diagnosis: Shell thick, inflated, with anterior end truncated or only slightly projected. Umbo wide, inflated, obliquely truncated, located at or close to anterior end. Outer shell surface with low and wide commarginal folds. Posterior area of shell wide, defined by a well-developed but narrow umbonal ridge. Hinge with teeth throughout the shell ontogeny. Nymph narrow. Description: Shell ≤ 23.0 mm long, usually low and rectangular, sometimes high and square or trapezoidal, sometimes greatly distorted; moderately to widely inflated, with the maximum width at about the posterior third of total shell length; very solid (Figs 3M–O, 8). Markedly inequivalve throughout ontogeny: right valve larger and wider than less valve, ventrally overlapping over less valve. Posterior end greatly projected, sometimes curved or recurved; anterior end abbreviated, truncated, rounded or shortly pointed, lower than posterior end. Posterior area of shell wide, depressed to flat; usually defined by a narrow, rounded to keeled umbonal ridge, indistinct in some specimens. Ventral and posterior gapes between valves ...