Schizochiton tasteti

Dell’Angelo, Bruno, Sosso, Maurizio & Taviani, Marco, 2025, The Cenozoic European Polyplacophora (Mollusca), Zootaxa 5704 (1), pp. 1-377 : 200-201

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-FF28-4ED8-0FAD-FCD06B5F91A3

treatment provided by

Plazi

scientific name

Schizochiton tasteti
status

 

Schizochiton tasteti View in CoL Dell’Angelo, Lesport, Cluzaud & Sosso, 2018

Fig. 99 View FIGURE 99

Schizochiton tasteti View in CoL Dell’Angelo, Lesport, Cluzaud & Sosso, 2018a, p. 38, figs 7M–T; Dell’Angelo et al. 2020b: tab. 7, 9.

Type material. Holotype: MHNBx 2017.7.4, head valve, width 2.3 mm ( Figs 99A–D View FIGURE 99 ). Paratype: MHNBx 2017.7.5, intermediate valve ( Figs 99E–H View FIGURE 99 ).

Type locality. Gaas , Lagouarde ( France) .

Type stage. Oligocene (Rupelian).

Material examined. Lower Oligocene: France: Gaas , Lagouarde: type material plus 2 head valves ( AC). Maximum width of the valves: 5.2 / 4.4 / -- mm .

Description. Tail valve unknown. Head valve semioval, front slope slightly convex, apex small and distinct. Intermediate valves polygonal, as long as wide (WT/LT = 1.05), semicarinate in anterior profile, elevated (H/W = 0.5), anterior margin straight in central part, almost straight and strongly slanting at pleurae, side margins short, posterior margin straight at both sides of moderately produced, bluntly pointed apex, lateral areas small, hardly or not raised.

HV sculptured with six raised rows of large pustules growing outward toward anterior margin, with deep holes on top of each pustule, interspaces between pustule rows with many large and well separated oval granules, smaller near apex and growing outward anterior margin. LA sculptured with an elevated diagonal row of large pustules with deep holes on top, and a more obsolete second radial row of pustules at posterior margin. PA sculptured with large oval granules, well separated near diagonal rows of pustules between PA and LA, becoming united and forming short segments, acquiring vaguely zig-zag pattern near JA, triangular, longitudinally finely striated, without any other sculpture.

Articulamentum with subrectangular apophyses, insertion plates long, slit formula 6 / 1 / --, slits shallow, corresponding to tegmental rows of pustules, slit rays indicated, teeth sharp, finely striated on the upper side.

Remarks. The deep V-shaped caudal sinus in the tail valve, one of the main characters of the genus Schizochiton Gray, 1847 ( Kaas et al. 2006: p. 49), is unfortunately not comparable in the studied specimens, lacking tail valves. However, the other characters are sufficient to attribute the valves examined to the genus Schizochiton . The valves are in some cases eroded, and, therefore, not characteristics are fully detectable in detail. The holes on the top of large pustules could be likely interpreted as eyepiece housing for the ocelli; this aspect is reported from living representatives of Schizochiton but are not, to the best of our knowledge, normally preserved in fossils species, as is the case of the specimens here figured. The holes seem deep, penetrating inside the valves.

Comparisons. Bielokrys (1999) described three species of Schizochiton from the Eocene of Ukraine: S. parcus , S. carinatus and S. hirtus , different from S. tasteti (see Dell’Angelo et al. 2018a for comparisons).

Distribution. Lower Oligocene: northeastern Atlantic (Rupelian): Aquitaine Basin, France: Gaas ( Dell’Angelo et al. 2018a).

AC

Amherst College, Beneski Museum of Natural History

Kingdom

Animalia

Phylum

Mollusca

Class

Polyplacophora

Order

Chitonida

Family

Schizochitonidae

Genus

Schizochiton

Loc

Schizochiton tasteti

Dell’Angelo, Bruno, Sosso, Maurizio & Taviani, Marco 2025
2025
Loc

Schizochiton tasteti

Dell'Angelo, B. & Lesport, J. - F. & Cluzaud, A. & Sosso, M. 2018: 38
2018
Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF