Costacopluma squiresi, Nyborg & Vega & Filkorn, 2023

Nyborg, Torrey, Vega, Francisco J. & Filkorn, Harry F., 2023, Validation of Costacopluma squiresi Nyborg, Vega & Filkorn (Crustacea: Brachyura: Retroplumidae) from the Pacific Slope, Paleocene of California, USA, Zootaxa 5315 (5), pp. 492-494 : 492-493

Costacopluma squiresi sp. nov.

( Fig. 1 )

Costacopluma squiresi Nyborg, Vega & Filkorn, 2009: 205–207 , fig. 2.

Type material. HOLOTYPE: LACMIP 13560, nearly complete carapace with right cheliped preserved, carapace length 11.2 mm, width 11.5 mm, collected from LACMIP locality 11688, Santa Susana Formation, Quarry Canyon, near head of Quarry Canyon , Southern California . PARATYPE: LACMIP 13561, length about 13.0 mm, width 15.8 mm, dorsal carapace and portions of thoracic sternum, collected from LACMIP locality 21580, San Francisquito Formation, about 3.5 km northwest of Warm Springs Mountain, Southern California .

Diagnosis. Carapace small, subtrapezoidal to subhexagonal elongated, widest at posterior one-fourth of carapace; marginal notch separating anterolateral from lateral margins; transverse ridges moderately strong, with sharp, granulated crests; areas between ridges ornamented with very fine granules. Thoracic sternum wide. Male abdomen triangular. Right cheliped massive.

Etymology. The species name honors Richard L. Squires, prominent paleontologist and prolific publisher on the stratigraphy and paleontology of the Pacific slope of North America.

Remarks. A full description and figures of Costacopluma squiresi and stratigraphic account are given by Nyborg et al. (2009).

Figures

FIGURE 1. Costacopluma squiresi sp. nov.: 1, dorsal view of carapace, holotype LACMIP specimen 13560, Paleocene, LACMIP locality 11688; 2, lateral view of right cheliped, holotype LACMIP specimen 13560; 3, dorsal view of carapace, paratype LACMIP specimen 13561, Paleocene, LACMIP locality 21580; 4, ventral view of carapace, paratype LACMIP specimen 13561. Scale bars = 1 cm.