Polybranchia orientalis, (KELAART, 1858)

POLYBRANCHIA ORIENTALIS ( KELAART, 1858) View in CoL

( FIGS 2–3, 5, 6G, 7, 8H–I)

Proctonotus orientalis Kelaart, 1858: 106 . Type locality: ‘ Trincomalie’ (= Trincomalee, Sri Lanka).

Type material

Original type material untraceable, not found at NHMUK. Original drawings available at the library of the NHMUK. Neotype (here designated): Vizhinjam, Kovalam, India, 20 Dec 2013, one specimen 20-mm long ( LACM 3487 About LACM ), illustrated by Ravinesh et al. (2014) .

Additional material examined

South of Lago de Oro Hotel , Verde Island Passage , Batangas, Luzon, Philippines, 11 May 2014, one specimen 35 mm live length, 11-mm long, isolate MM120 ( CASIZ 199384 ) . Calumpan Peninsula , Mainit ‘ Bubbles’, Batangas, Luzon, Philippines, 16 April 2008, one specimen, 10-mm long, isolate MM068 ( CASIZ 177601 ) .

Description

External morphology: Body translucent brown with minute dark brown spots covering entire surface in some specimens, giving animal dark appearance ( Fig. 5A). Rhinophores translucent, with single pale brown line and minute brown specks throughout; small translucent papillae without colour evenly distributed on their surface ( Fig. 5B). Pericardium white, typically very conspicuous. Ceratal peduncle with snowy white pigment in depression. Cerata fan-shaped, translucent and speckled with cinnamon brown throughout, with two dorso-medial yellowish patches, some with single black dot ( Fig. 6G). Two large papillae on dorso-medial surface of each ceras; one large, yellow, near ceratal tip; another smaller, yellow, below first papilla. Additional papillae on dorsal and ventral cerata surface white, minute and inconspicuous. Cerata margin outlined with pale yellow. Foot colour unknown.

Internal morphology: Radular tooth count unavailable for 35-mm long specimen from the Philippines ( CASIZ 199384), but active tooth with two rows of 13 blunt denticles on convex ventral surface ( Fig. 7A); decreasing in size toward hooked cusp ( Fig. 7A, C). For 10-mm long specimen from the Philippines ( CASIZ 177601), the total number of radular teeth unknown; seven teeth in ascending limb ( Fig. 7B). Ascus not observed in either specimen available ( CASIZ 199384; CASIZ 177601); number of pre-radular teeth unknown.

Penis elongate, smooth and slender; cylindrical from base to just below tip. Tip flattened, lacking penial stylet ( Fig. 8H–I).