Callistochiton borellianus

Dell’Angelo, Bruno, Sosso, Maurizio & Taviani, Marco, 2025, The Cenozoic European Polyplacophora (Mollusca), Zootaxa 5704 (1), pp. 1-377 : 170-171

publication ID	https://doi.org/10.11646/zootaxa.5704.1.1
publication LSID	lsid:zoobank.org:pub:747DFE8B-156A-493A-8817-5F861C4D6319
persistent identifier	https://treatment.plazi.org/id/03FEF726-FF46-4EBA-0FAD-F8CD6B5F900A
treatment provided by	Plazi
scientific name	Callistochiton borellianus
status

Treatment

Callistochiton borellianus Dell’Angelo, Giuntelli, Sosso & Zunino, 2015

Fig. 84 View FIGURE 84

Callistochiton borellianus Dell’Angelo, Giuntelli, Sosso & Zunino, 2015a, p. 236, pl. 6, figs 14–18; Dell’Angelo et al. 2020b, tab. 3, 5.

Type material. Holotype MGPT PU 108786 , intermediate valve, width 5.7 mm ( Figs 84A–D View FIGURE 84 ).

Type locality. Borelli ( Piedmont, Italy) .

Type stage. Miocene (Tortonian).

Material examined. Miocene (Tortonian). Italy: Borelli : type material .

Description. Head and tail valves unknown. Intermediate valve solid, broadly rectangular (W/L = 1.98 estimated), carinate in anterior profile, elevated (H/W = 0.61), anterior and posterior margins straight, side margins rounded, slightly bilobated, apices inconspicuous, lateral areas raised, distinctly defined.

LA sculptured with two nodulose ribs of different width, rib near the diagonal ridge wider, crossed by numerous concentric grooves, and separated by narrow, deep sulcus. CA sculptured with 11 longitudinal, elevated, granulose riblets, becoming larger towards the lateral margins, JA large, smooth, only marked by some growth lines.

Articulamentum with apophyses wide, insertion plates well developed, apical area prominent, teeth not pectinated, a single short slit for each side, slit rays hardly discernible.

Remarks. Callistochiton borellianus Dell’Angelo, Giuntelli, Sosso & Zunino, 2015 is known only for a unique intermediate valve from the upper Miocene of N. Italy. The valve is partly eroded, but the diagnostic characters are very distinctive and well defined.

The unique intermediate valve has been assigned to the genus Callistochiton on the basis of strong similarities to species included in this genus ( Dell’Angelo et al. 2015a), and represents the first record of this genus for the Italian Miocene.

Comparisons. See Tab. 13 for a comparison with the Callistochiton spp . considered in the present study.

Distribution. Upper Miocene: Proto-Mediterranean Sea (Tortonian): Po Basin, N Italy: Borelli ( Dell’Angelo et al. 2015a).

Kingdom	Animalia
Phylum	Mollusca
Class	Polyplacophora
Order	Chitonida
Family	Callistoplacidae
Genus	Callistochiton