Breviturma pusilla (Brock 1888)

Ophiocoma pusilla (Brock)

Ophiomastix pusilla Brock, 1888, p. 499 (Amboina).—Pfeffer, 1900, p. 85 (Temate, no other data).—Koehler, 1905, p. 65, pl. 6, figs. 9, 10, pl. 13, fig. 3 (Moluccas).—Ailsa M. Clark, 1967, p. 45, fig. 5 (Red Sea, Aqaba). Ophiocoma pusilla (Brock).—H. L. Clark, 1921, p. 131. Ophiocoma latilanxa Murakami, 1943a, p. 194, fig. 13 (Palao); 1943b, p. 217 (Ryukyu).

Ophiocoma sp.—Ailsa M. Clark, 1952, p. 208 (Red Sea).

Ophiocoma insularia Lyman.—Balinsky, 1957, p. 26 (Mozambique).

Ophiocoma insularia var. variegata Smith.—H. L. Clark, 1938, p. 330 (part, Lord Howe Island).

Ophiocoma scolopendrina (Lamarck).—H. L. Clark, 1921, pl. 13, fig. 9 (color) (Torres Strait).

STATUS OF TYPE MATERIAL.—In the original description of Ophiomastix pusilla, Brock gave the size of his largest individual as 8 mm (d.d.), with a disc-diameter-to-arm-length ratio of 1:5. Aside from this, there was no indication that a specific individual was being described nor was there any type designation. Brock mentioned only, “wurde von mir in zahlreichen Ex-emplaren in Amboina erbeutet” (Brock, 1888, p. 500).

Dr. P. Kuenzer at the Göttingen Museum informed me that Brock’s original specimens deposited there were destroyed in World War II. Apparently, however, two specimens from Brock’s original series were transferred to the Zoologisches Museum Berlin prior to that time. These specimens have been examined and, although smaller than Brock’s largest specimen, they are considered part of the syntypic series. The fact that the two specimens differ slightly in certain external characters (with one showing more evidently the characters originally presented by Brock) leads me to designate a lectotype in this paper. Some of the more important features and variations of the two specimens are given below in the description of the species.

LECTOTYPE.—ZMB 5429 (Marine Tiergruppen); disc diameter, 4 mm. Label with specimen: “Ophiomastix pusilla, Amboina 5429 Brock. Type.”

PARALECTOTYPE: ZMB 4777 (Marine Tiergruppen); disc diameter, 3.5 mm.

DIAGNOSIS—Disc diameter up to 10 mm; sexually mature specimens from 6 mm (Eniwetok, September 1966). Small, uniformly distributed granules entering oral interradial area but not reaching oral shields and leaving an area near genital openings with exposed scales (paralectotype with several widely spaced spiniform granules among normal granules near edge of disc aborally). Two tentacle scales each side of proximal arm segments (lectotype with two scales to segment 22; larger specimen, d.d. 7.5 mm, with two scales to segment 40); outer scale largest. Arm spines typically long, tapering, fragile, and hollow (lumen of spine greater than thickness of spine wall) also not smooth; occasional thickening of one to three adjacent, next to uppermost arm spines occurring from segments 8 to 12; enlargement of outer part of these spines also combined with increased length of these modified spines, in alcohol appearing as a gelatinous epithelial envelope around spine (lectotype with enlarged spines only on one side of 10th segment of three arms; paralectotype without enlarged spines). Arm spine sequence for 7-mm specimen: 3-3-4-4(or 5)-5(or 4)-5 (or 6)-5 (rarely 6)-5-5-5 for the proximal ten segments; beyond segment 6, development of fifth arm spine on more segments with size increase to segment 20 (lectotype with five spines to segment 8); distally. number of spines 4 then, near arm tip, 3. Oral papillae 3, less often 4, outer papilla broadest, its outer margin overlapping inner edge of buccal tentacle scale. Dental papillae in two and three rows, marginal papillae slightly larger than medial ones; from 6 to 15 papillae depending on size (lectotype with 6–8 in two rows). One to four granular papillae above (oral to) apex of each jaw. Dental plate (Figure 26) with widened lower portion, narrow septa dividing teeth foramina; length-to-width ratio, 2.3–2.7 : 1. Teeth 3 or 4; oralmost shortest and narrow, second and third longer and narrow; tips of teeth hylinated. Oral shields longer than wide; length-to-width ratio, 1.2 to 1.7 : 1 (lectotype, 1.3 : 1; in no case were these plates noted to be twice as long as broad, as originally indicated by Brock). Adoral shields widely separated, triangular, outer edge in contact with ventral shield; limited to sides of mouth shields. Oral plate (jaw) lacking ridges and grooves on abradial muscle surface (see Murakami, 1963, pl. VII, fig. 11). Upper arm plates with margin broadly arched distally and tapering sharply proximally (Figure 29). Lower arm plates with convex distal margin, tapering proximally. Arms banded in most cases, dark brown and lighter yellowish or white; dark aboral arm plates often with various mottled pattern, or uniform tan to black; oral surface of arms lighter than aboral surface. Disc spotted, reticulated, or solid color (brown or gray), usually with white spot on either side of each arm base; periphery of disc sometimes gray with median white area and a dark gray spot centrally located (lectotype with tan disc and lighter ambital area).