Crassatella pedroi, Devries, 2016

Devries, Thomas J., 2016, Fossil Cenozoic crassatelline bivalves from Peru: New species and generic insights, Acta Palaeontologica Polonica 61 (3), pp. 661-688 : 670-671

publication ID

https://doi.org/ 10.4202/app.00228.2015

persistent identifier

https://treatment.plazi.org/id/AF5F87F5-FFED-FF85-FFDA-F96AFEDEFD22

treatment provided by

Felipe

scientific name

Crassatella pedroi
status

sp. nov.

Crassatella pedroi View in CoL sp. nov.

Fig. 6G View Fig .

Etymology: From “Pedro”, informal name for Inkayacu paracasensis , an Eocene penguin unearthed nearby.

Holotype: Articulated paired adult valves: UWBM 101833 About UWBM , L 38.4, H 30.8, T 8.6.

Type locality: B8341, near Playa Yumaque, East Pisco Basin, Peru.

Type horizon: Very base of Otuma depositional sequence, lower Priabonian.

Material.—B8329, six broken specimens.

Diagnosis.—Anterior of shell compressed. Commarginal ribs extend beyond umbo.

Description.—Shell about 40 mm long, quadrate, anterior compressed, L:H ratio 1.25, T:H ratio 0.2, maximum inflation ventral to beak. Anteriodorsal and posteriodorsal margins straight, anterior margin sharply rounded, posterior margin broadly truncate, ventral margin rounded with slight angulation. Weakly angular posterior ridge diverging 20−25° from posteriodorsal margin. Secondary posterior ridge obsolete. Lunule twice as wide as escutcheon; both about two-thirds the length of respective margins. Beak prosogyrate. Umbo rounded, orthogyrate, with broad commarginal ribs extending ventrally 20 mm; ribs absent posterior to primary posterior ridge. Remainder of exterior with irregular commarginal growth lines. Interior of valves not visible. Inner ventral margin smooth.

Remarks.—Despite the absence of visible hinge characters, the paired specimen of Crassatella pedroi can be distinguished from specimens of C. neorhynchus by its anterior compression ( Fig. 6G View Fig 1 View Fig ) and commarginal ribs extending well beyond the umbo ( Figs. 6G View Fig 2 View Fig , G 3 View Fig ). Furthermore, the lunule is narrowly cordate ( Fig. 6G View Fig 1 View Fig ) and both it and the escutcheon are proportionally longer than their counterparts on specimens of C. neorhynchus . The widely spaced umbonal ribs distinguish C. pedroi from the slightly younger C. rafaeli sp. nov. from the Otuma depositional sequence.

Stratigraphic and geographic range.—Priabonian, basal Otuma depositional sequence, East Pisco Basin, south-central Peru.

Kingdom

Animalia

Phylum

Mollusca

Class

Bivalvia

Order

Carditida

Family

Crassatellidae

Genus

Crassatella

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