Delectopecten, STEWART, 1930

Hickman, Carole S., 2023, Paleogene marine bivalves of the deep-water Keasey Formation in Oregon, Part II: The pteriomorphs, PaleoBios 40 (5), pp. 1-51 : 24-25

publication ID

https://doi.org/ 10.5070/P940561331

publication LSID

lsid:zoobank.org:pub:1756B24A-813B-423F-896F-91B21FF58A79

DOI

https://doi.org/10.5281/zenodo.10913549

persistent identifier

https://treatment.plazi.org/id/C23987DD-FFE1-2926-FC4A-FCF7EDB8B971

treatment provided by

Felipe

scientific name

Delectopecten
status

 

DELECTOPECTEN STEWART, 1930 View in CoL

Type species—by original designation, Pecten (Pseudamussium) vancouverensis Whiteaves (1793) View in CoL . Holocene, North Pacific. Pliocene of California .

A peculiar form of surface ornamentation, defined by Waller (1972b) as camptonectes microsculpture, covers the surface exterior of both valves in geometrically regular patterns of very fine foliated calcite striae (Waller 1972a, b). The striae are oblique or antimarginal, forming a variety of net-like patterns in which elements are neither radial (continuously produced) nor commarginal (periodically produced and conformable with the shell margin). Classifications of antimarginal sculpture are supported by computer simulations (e.g., Hayami and Okamoto 1986) and theoretical morphospaces including camptonectes patterns (Ubukata 2005). Other forms of divergent sculpture occur on the exterior surface of bivalve shells, although their taxonomic significance is less clear than their microstructural expression and potential functional roles. However, the microscopic, foliated calcite striae, also referred to by some authors as “diverging scratches,” “radial scratches,” or “antimargial striae” (e.g., Dijkstra 1991), are treated as a clade within Pectinidae View in CoL (e.g., Habe 1977, Waller and Marincovich 1992, Dijkstra and Kastoro 1997, Dijkstra and Gofas 2004, Bouchet and Rocroi 2010, Carter et al. 2011, Coan and Valentich-Scott 2012).

The North Pacific living and fossil Delectopecten vancouverensis View in CoL , type species of the genus, has microscopic camptonectes sculpture on both valves ( Fig. 16A, B View Figure 16 ) that is comparable to that of the new species in the Keasey Formation described below. The type species also has a prominent anterior auricle ( Fig. 16B View Figure 16 ), deep byssal notch with ctenolium ( Fig. 16C View Figure 16 ), and poorly delineated posterior auricle that is continuous with the posterior margin of the disc ( Fig. 16A View Figure 16 ). Delectopecten vancouverensis View in CoL is especially pertinent to interpretation of Pacific coast fossil Delectopecten View in CoL because of its tolerance to severe hypoxic conditions (0.0–0.2 ml/l O2) (Suarez-Mozo et al. 2019). It occurs in assemblages that include chemosymbiotic solemyid and lucinid bivalves as well as other oxygen minimum zone taxa capable of tolerating hypoxia (Levin 2003).

Delectopecten View in CoL is cosmopolitan in distribution and has been considered a descendant of the Jurassic–Cretaceous Camptonectes Agassiz in Meek (1864) (Waller 1972a, b). Although the Cenozoic fossil record of Delectopecten View in CoL is best documented taxonomically in strata of the west coast of North America (MacNeil 1967, E.J.Moore 1984b), it is well represented and often abundant in Japanese deep-water facies. However, Paleocene occurrences in Australia ( Darragh 1997) and Argentina (del Rio et al. 2008) as well as Late Cretaceous pectinids with camptonectes sculpture from New Zealand and the Chatham Islands ( Crampton 1988) are consistent with hypothesized long cosmopolitan history.

Stratigraphic range—Lower Paleocene (Danian)– Holocene.

Kingdom

Animalia

Phylum

Mollusca

Class

Bivalvia

SubClass

Pteriomorphia

Order

Pectinida

Family

Pectinidae

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