Notobryon clavigerum Baba, 1937

Location: Futou beach, Tago, Futou, Dougashima, Shizuoka, Japan
Date: 2016/03/04
Length: 20mm
Depth: 5.0m
Water temperature: 15.0℃

Description

A large notobryid, body length about 80 mm. The head forms an expanded semicircular veil with a wavy margin. The rhinophore sheath has a longitudinal crest along both the anterior and the posterior margin — the most diagnostic external character of this species. Of the dorso-lateral lobes, the posterior pair are slightly smaller than the anterior; the lobes are smooth-edged except at the tip, which curls outward bearing a row of small claw-like papillae (5 on each anterior lobe, 3 on each posterior lobe). The branchiae are large dendritic tufts, 3-4 on each anterior and posterior lobe with one further tuft on the rear of the back. The tail is long and bears a low smooth-edged crest in the middle line, with a row of small conical tubercles along each side.

From the coloured field sketch the animal is yellowish with blue markings mainly on the upper sides of the dorso-lateral lobes and the body sides.

Distribution

Type locality: Amadaiba, Sagami Bay, Japan (about 91 m).

Etymology

The specific epithet clavigerum is the neuter form of a Latin compound from clava ("club, claw") and -ger ("bearing"), "claw-bearing", in reference to the row of claw-like papillae at the tips of the dorso-lateral lobes.

Remarks

Distinguished externally from Notobryon wardi and Notobryon bijecurum by (1) the 3-5 claw-like papillae at the tip of the dorso-lateral lobes and (2) a longitudinal crest along both the anterior and posterior margins of the rhinophore sheath (other congeners have only a posterior crest).