Echinoderes pennaki Higgins 1960

Echinoderes pennaki Higgins

Echinoderes pennaki Higgins, 1960:86; 1961:81.—Chitwood, 1964b:3.—Higgins, 1964a:246; 1964b:479.—Kirsteuer, 1964:389.—Higgins, 1966a:120; 1966b:519; 1967:75.—Schmidt, 1974:13.—Boykin, 1974:40.

REDESCRIPTION.—Holotypic adult female (Figures 22–25), trunk length, 404 μm; MSW–8, 62 μm, 15 percent of trunk length; SW, 56 μm, 14 percent of trunk length.

Second segment with 16 anteriorly rounded placids; midventral placid slightly truncate, distinctly larger than adjacent placids; trichoscalid plates on sides of midventral placid indented slightly on anterior margin, short and broad, trichoscalid plates on dorsal surface similar but equally as broad as long.

Segments 3–12 with prominent hairs (10–15 μm), pattern distinctive (Figures 22–23); posterior border of segments 3–11 with pectinate fringe both dorsally and ventrally, fringe on ventral surface of segment 3 almost spinose, more finely pectinate on remaining segments, slightly evident near posterior border of 12th sternal plates; terminal segment with minute hairs on border of tergal and sternal plates, posterior margin of tergal plate deeply incised forming pointed extensions mesial to base of each lateral terminal spine, sternal plates broadly rounded without spinous extensions (Figures 24, 25).

Middorsal spines on segments 6–10, increasing uniformly in length, 48–70 μm, mean length 59.6 μm, 15 percent of trunk length; lateral spines on segments 7–11, L–4 (=adhesive tube) absent although a scar, or perhaps a sensory spot, located slightly mesial to usual position of L–4; L–7 shorter (14 μm) than remaining lateral spines (32–36 μm) subequal in length, mean length of lateral spines 29.8 μm, 7 percent of trunk length; lateral terminal spines long, 156 μm, 39 percent of trunk length; lateral terminal accessory spines 52 μm in length.

Pachycycli well developed, forming distinctive pattern at ventral midline and superficial to attachment of lateral terminal spine muscles on segment 13; small muscle scars visible near midventral line of segments 3–4, 7, 11, and 12, more prominent scars dorsolaterally on segments 3, 5–12; sensory spots situated ventrolaterally on segment 3 and possibly on segment 4 (possibly adhesive tube openings?).

MATERIAL EXAMINED.—4 adult females including holotype (USNM 29746) and 3 paratypes (USNM 29747); col. P. L. Illg, 16 July 1958, East Sound, Orcas Island, Washington, USA, from a depth of 32 meters.