Kelliella miliaris Philippi 1844

Kelliella miliaris (Philippi, 1844)

Fig. 9 a–d

Venus miliaris Philippi, 1844 (p. 36, pl. 14, fig. 15).

Kellia abyssicola Forbes, 1844 (p. 192).

Kelliella abyssicola Sars M., 1870 (p. 89, pl. 12, figs. 11–15; pl. 13, figs. 16–26).

Kelliella abyssicola (Forbes) — Di Geronimo & Panetta 1973 (p. 102); Di Geronimo 1974 (p. 155); Di Geronimo et al. 2001 (pl. 1, figs. 7–8); Rosso et al. 2010 (fig. 11 C).

Kelliella miliaris (Philippi, 1844) — Thomsen & Vorren 1986 (pl. 7, fig. E); Studencka 1987 (p. 74, pl. 32, figs. 3–4); Palazzi & Villari 2001 (p. 27); Petersen 2004 (p. 88, fig. 81); Oliver et al. 2016 (online resource).

Kelliella abyssicola (Forbes, 1844) — Cossignani et al. 1992 (fig. 365); Repetto et al. 2005 (p. 337, mid right fig.); Peñas et al. 2006 (figs. 396–397); Tabanelli 2008 (pl. 5, fig. 6).

Kelliella miliaris Philippi, 1844 — Allen 2001 (p. 201, figs. 1–2).

Kelliella miliaris (= abyssicola)— Ceregato et al. 2007 (fig. 3.1).

Diagnostic characters. Roundly oval, inequilateral thin shell; shorter anterior side; two subhorizontal cardinal teeth in each valve, the weaker one peg-like; stronger tooth reverse-V shaped in the right valve and spoon-shaped in the left valve; outer surface with growth lines only. Prodissoconch: shell type ST-2A; length about 200 µm (P-1 about 70 µm); roundish outline; convex profile; P-1 surface irregularly pitted; P-1/P-2 boundary ill-defined; P-2 with commarginal growth welts; transition to the nepioconch faint.

Remarks. The name miliaris (Philippi, 1844) seems to shortly predate abyssicola (Forbes, 1844) which is consequently regarded as a junior synonym of the former taxon. Kelliella abyssicola M. Sars, 1870, is a secondary homonym and subjective synonym of abyssicola (Forbes, 1844) (CLEMAM 2016; Gofas & Bouchet 2014). The recently erected Caribbean species K. abyssicola Allen, 2001, has been excluded from Kelliella and doubtfully assigned to Vesicomya (WoRMS 2016). Studencka (1987) regarded K. abyssicola (Forbes, 1844) as an exclusively fossil (Lower Pliocene) taxon.

Occurrence. Box corer samples BC04 (45 specimens), BC05 (69), BC06 (3), BC10 (1), BC11 (111), BC66 (144), BC67 (47), BC68 (6), BC71 (2), BC72 (882); cores BC04 (177), BC05 (646), BC06 (1), BC21 (990), BC51 (906), BC52 (37), BC67 (111), BC72 (1290). Maximum length: 2.5 mm.

Distribution and habitat. Kelliella miliaris is distributed along the entire Atlantic margin and across the Mediterranean, including the Levantine basin; it is an infaunal element dwelling on sandy to clayey bottoms from 10 to 1170 m depth (down to 850 m in the Mediterranean), indicating organic rich substrates with low sedimentation rates and hypoxic conditions (Studencka 1987; Cossignani et al. 1992; Buhl-Mortensen & Høisaeter 1993; Pons-Moyà & Pons 1999; Allen 2001; Galil 2004; Ceregato et al. 2007; Oliver et al. 2016). It is seemingly the only Kelliella species thriving at bathyal depths, while all other Atlantic and Pacific species seem to be exclusively abyssal and hadal (Allen 2001). It characterizes the Abra-Nucula biocoenosis in the bathyal of Taranto (Geronimo & Panetta 1973). In the Santa Maria di Leuca CWC biotope, it was found on muddy bottoms around coral colonies (Mastrototaro et al. 2010), being very abundant in mollusk mud and foraminifer mud thanatofacies, abundant in Gryphus-Isidella thanatofacies, and common in coral rubble thanatofacies (Rosso et al. 2010).

Fossil record. Middle Miocene of Poland; Pliocene of northern Italy; Pleistocene of Sicily (type locality), Sardinia, southern Italy, Denmark and Rhodes (Di Geronimo & Bellagamba 1985; Studencka 1987; Di Geronimo & La Perna 1997; Petersen 2004; Di Geronimo et al. 2005; Ceregato et al. 2007). K. miliaris characterizes a Piacenzian hypoxic bathyal paleocommunity at Campore (northern Italy) along with Delectopecten vitreus (Ceregato et al. 2007).