Callochitonidae Plate, 1901

Family Callochitonidae Plate, 1901 View in CoL

Genus Callochiton Gray, 1847

Type species. Chiton laevis Montagu, 1803 (non Pennant, 1777) = Callochiton septemvalvis ( Montagu, 1803) View in CoL , by subsequent designation (Gray 1847)

Distribution. Callochiton is known from the Oligocene up to the Recent, with a living distribution in the Indo-West Pacific (including Japan), eastern Atlantic Ocean, and subantarctic waters ( Kaas & Van Belle 1985b). The fossil record includes the Oligocene of New Zealand ( Ashby 1929; Lee et al. 2014; Wu & Lee 2024), the Miocene of Europe ( Šulc 1934; Bałuk 1984; Dell’Angelo et al. 2016), Argentina ( Urteaga et al. 2011) and Australia ( Ashby 1939), the Pliocene/Pleistocene of Europe ( Koskeridou et al. 2009; Dell’Angelo et al. 2011, 2004, 2013), New Zealand ( Sutherland et al. 1995), the Pleistocene of Japan ( Itoigawa et al. 1976), Red Sea ( Dell’Angelo et al. 2020a), Greece ( Garilli et al. 2005), and Italy ( Sabelli & Taviani 1979; Dell’Angelo & Giusti 1997), and the Holocene of Patagonia ( Gordillo & Schwabe 2009).

Remarks: Recent molecular phylogenetic analyses support the division of Polyplacophora into three orders, Lepidopleurida , Callochitonida and Chitonida ( Giribet & Edgecombe, 2020; Irisarri et al. 2020; Moles et al. 2021; Liu, Sigwart & Sun 2023).

Three extant species of Callochiton are known from the Neogene and Pleistocene of the circum-Mediterranean area: C. septemvalvis ( Montagu, 1803) , C. doriae ( Capellini, 1859) , and C. calcatus Dell’Angelo & Palazzi, 1994, and other two species only known as fossils are described from the Neogene of Europe: Callochiton pouweri Dell’Angelo, Landau, Van Dingenen & Ceulemans, 2018 and C. zigzag Šulc, 1934 . The main morphological characters of the Callochiton spp . considered in the present study are reported in Tab. 8.