Bathyraja kincaidii ( Garman , 1908 )

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 : 5-6

Bathyraja kincaidii ( Garman, 1908)

Description: The egg cases of Bathyraja kincaidii ( Figure 4) are very small, 50 to 66 mm in length, with MAW about 76–91% of ECL. Egg case dorsal surface covered with thin layer of fine fibers, ventral surface with either a very thin fibrous layer or without. Surface of egg case beneath fibrous layer finely striated with longitudinal rows and smooth to the touch. LKW very broad, about 14–19% of MAW, and extending length of case including outer edge of horns; a keel is present along inner edge of the posterior horns, but absent on anterior horns. Attachment fibers present along entire edge of lateral keels. Anterior apron border broad, concave; anterior horns about 50–80% ECL, and flattening towards tips becoming thread­like. Anterior horns curve perpendicular to dorsal aspect of egg case and hooking rearward. Posterior apron border broad, nearly straight, transverse, about 3–9 mm wider than anterior apron. Posterior horns moderately long, length similar to ECL, curved inward to median aspect of egg case, flattening toward tips, and becoming thread­like. Egg cases from preserved specimens range from a light to dark brown except for lateral keels which are usually lighter brown to gold colored.

Remarks: The egg case described and depicted by Cox (1963) for this species appears to be consistent with our findings in that it is a small egg case, nearly as wide as long, has attachment fibers present, and prominent lateral keels. Our description differs in that we found the egg cases of B. kincaidii to be smooth to the touch while Cox (1963) described the surface texture as moderately rough. Since we do not know the location of where those egg cases were collected or their eventual deposition we are unable to directly compare our egg cases with those of Cox (1963). It may be that the slight differences we observed in our samples are within the normal range of variability. Bathyraja kincaidii , however, may represent a species complex of two or more distinct, sympatrically occurring species ranging between the Gulf of Alaska and California. Therefore, careful examination of egg cases from throughout this region may help elucidate this question.

Material examined: CAS 224339, 48.2 cm TL, off Davenport, California (ca 36.5368 N, ­ 122.1445 W), 170 m, 3 August 2002; MLML BK0209­6, 50.1 cm TL, off Davenport, California, (ca 36.5368 N, ­ 122.1445 W), 181 m, 21 September 2002; MLML BK0210­7: 50.0 cm TL, off Davenport, California (ca 36.5596 N, ­ 122.2220 W), 311 m, 24 October 2003; MLML BK 121503 ­4­1, 53.5 cm TL, off central Oregon (45.7385 N, ­ 124.3820 W), 153 m, 13 September 2003; MLML BK 102403 ­02­3, 56.9 cm TL, off northern California (40.2276 N, ­ 124.5422 W), 360 m, 5 October 2003.