Pectinodonta borealis Nakrem 2017

Dataset
Gastropods from the Late Jurassic - Early Cretaceous seep deposits in Spitsbergen, Svalbard: Rank
SPECIES: Published in
Nakrem, Hans Arne (2017): Gastropods from the Late Jurassic - Early Cretaceous seep deposits in Spitsbergen, Svalbard. Zootaxa 4329 (4): 351-374, DOI: 10.11646/zootaxa.4329.4.3

Classification

kingdom
Animalia: phylum
Mollusca: class
Gastropoda: family
Pectinodontidae: genus
Pectinodonta: species
Pectinodonta borealis

description

2015 Acmaeidae gen. et sp. indet.; Hryniewicz et al. 2015 a, table 1.

diagnosis

Diagnosis: Surface covered with thick commarginal ribs. Aperture elongated, oval. Apex slightly subcentral. Holotype: PMO 217.516, H = 1.8 mm, L = 4.1 mm, W = 3.3 mm.

discussion

Remarks. The concept of genera in Pectinodontidae is based mainly on radular characters (Sasaki et al. 2003). A slight difference in the apex position delimits, though tenuously, the shells of Pectinodonta and Bathyacmaea. The Sassenfjorden limpet has a slightly subcentral apex, so we decided to place it, though with hesitation, in Pectinodonta. The most similar species to? Pectinodonta borealis sp. nov. is Pectinodonta waitemata Marshall, 1985, from Miocene flysch deposits with plant and wood material from New Zealand. Pectinodonta waitemata also has strong concentric ridges and faint radial ornament; however, its apex is positioned much more eccentrically. The Oligocene Pectinodonta palaeoxylodia Lindberg & Hedegaard, 1996 from a wood-fall in Washington State, USA differs in having a stronger radial ornament than commarginal (Lindberg & Hedegaard 1996).

distribution

Distribution. Type locality only.

etymology

Etymology. Northern in Latin.

materials_examined

Type locality and age: Seep # 9, Sassenfjorden, Svalbard; late Berriasian, Early Cretaceous. Other material: Two additional specimens (one illustrated PMO 224.752) from the type locality. Description. Protoconch not preserved. Shell patelliform, elongate, oval; width is 81 % of length. Apex moderately high, heavily eroded, situated slightly subcentrally; height is 43 % of length. Shell exterior covered with thick concentric ribs. Radial ornament very weak, consisting of straight and faint radial riblets. Apertural margin straight in lateral view. Muscle scars not visible.

Name

Homonyms: Pectinodonta borealis Nakrem 2017