Bathyraja spinossisima ( Beebe & Tee­Van, 1941 ), Beebe & Tee-Van, 1941

Ebert, David A. & Davis, Chante D., 2007, Descriptions of skate egg cases (Chondrichthyes: Rajiformes: Rajoidei) from the eastern North Pacific, Zootaxa 1393, pp. 1-18 : 8-9

Bathyraja spinossisima ( Beebe & Tee­Van, 1941)

Description: The egg case of Bathyraja spinossisima ( Figure 6) is large, about 92 mm in length excluding horns, with MAW of 73% ECL. The surface is weakly striated, with both dorsal and ventral surfaces being plush to the touch. LKW is very narrow, about 3% of ECL, and extending onto horns. Attachment fibers are absent. Anterior apron broadly concaved, curving perpendicular from horizontal plane of egg case, and narrowing at tips. Posterior apron about 7 mm wider than anterior, nearly straight, broad, and transverse. Posterior horns about two­thirds ECL, curved inwards, and narrowing to tips. Egg case color after preservation is a uniform plum brown.

Remarks: A single egg case originally identified by Follett (1952: Figure 1 ) as that of Bathyraja trachura based on a near term embryo found inside was subsequently described by Cox (1963). This egg case has also been inaccurately illustrated in the literature as being that of B. trachura ( Eschmeyer et al., 1983; Mecklenberg et al., 2002; Ebert, 2003). However, Ebert (2005) examined this egg case and embryo (CAS 25617), and compared it with egg cases removed in utero from B. trachura , and concluded that the embryo fit that of the holotype of B. spinossisima . Miller and Lea (1972) first reported the occurrence of B. spinossisma from the ENP based on this specimen, but without explanation, only giving the museum catalogue number where it is deposited. At the time Follett (1952) and Cox (1963) identified this egg case as B. trachura , B. spinossisima had not been reported from the ENP.

The holotype of B. spinossisima is an embryo that had been removed from an egg case collected in very deepwater off Panama. Interestingly, a pair of egg cases also collected off Panama, in very deepwater, by Garman (1899) in some aspects appears to fit the description of this species. Unfortunately, the egg case for the holotype of B. spinossisima and Garman’s egg cases have been lost.

Material examined: CAS 25617, egg case with embryo present, Mulberry Seamount, 78 km west of Point Montara, central California (37.2630 N, ­ 123.2842 W), 1400 to 2000 m, 8 February 1950.

Figures

FIGURE 1. Skate egg case terminology and measurements.