Palola Lizard

Schulze, Anja, 2015, Six genetically distinct clades of Palola (Eunicidae, Annelida) from Lizard Island, Great Barrier Reef, Australia, Zootaxa 4019 (1), pp. 695-706 : 699-700

Palola Lizard Island Clade 1

( Fig. 2 A–C)

Material examined. AM W.43974, MI QLD 2344, sequenced; AM W.44034, MI QLD 2352 (3, 1 sequenced and photographed); AM W.44146, MI QLD 2356 (3, 1 sequenced and photographed); AM W.44128, MI QLD 2358, sequenced; AM W.44136, MI QLD 2358, sequenced; AM W.44894, MI QLD 2401, sequenced; AM W.44655, MI QLD 2398; AM W.44656, MI QLD 2398; AM W.44925, MI QLD 2390; AM W.44202, MI QLD 2359; AM W.43912, MI QLD 2335.

Description. Specimens small and threadlike. Anterior fragments examined for all sequenced specimens, ranging in length from 7 to 18 mm and from 0.6 to 1.7 mm in width; with 38–78 chaetigers. Branchiae only observed in one specimen (AM W.44034) from chaetiger 62 to the end of the fragment. No ventral eyespots. Head and body generally without pigmentation but with iridescent shine, or, if pigmentation is present light brown and restricted to prostomium and peristomium ( Fig. 2 A). Mandibles usually protruding from mouth, thin and nearly transparent with serrated anterior margin ( Fig. 2 B). Maxillae not examined. Antennae, palps and peristomial and parapodial cirri without pigment. Antennae and palps wrinkled, in preserved material, tapering and pointy tip. Median antenna reaches to chaetiger 2 or 3, lateral antennae reach to chaetiger 1 or 2 and palps reach to first or second peristomial ring. Tapering peristomial cirri reach forward to about 3/4 of the length of first peristomial ring. Eyes dark, oval or with ventral notch and nestled between lateral antennae and palps. Acicula brown. Other chaetae not examined. Dark pigment spots on dorsal side of posterior parapodia observed in two specimens (AM W.44034; AM W.44.136) ( Fig. 2 C).

Remarks. Although only distantly related in the phylogenetic tree and representing different species groups, Palola Lizard Island clade 1 is morphologically most similar to clade 5. Members of both clades are thin and threadlike, almost entirely lack pigmentation and have relatively thin and transparent mandibles. They can be distinguished by the relative length of the first and second peristomial rings: in clade 1, the first peristomial ring is 1.5 to 2 times as long as the second when viewed in the midlateral line where as in clade 5 they are more similar in length. Despite the morphological similarities, COI sequences are 26.9% divergent (Kimura-2-Parameter model) between clades 1 and 5. Palola Lizard Island Clade 1 falls into species group A and is the sister group to a clade with an extremely wide geographic distribution throughout the tropical Eastern and Western Pacific, referred to as clade A 1 in Schulze (2006) and Schulze & Timm (2012). The average genetic distance to this clade is only 1.9% and the two might represent the same species, although they are reciprocally monophyletic.

Figures

FIGURE 2. Palola Lizard Island clades 1 (A – C) and 2 (D – F). Specimens shown in A – C and F ethanol preserved; specimen shown in D and F fixed in formalin and later transferred to to 70 % ethanol. Labels in A – C serve as a reference for all following figures. A. Palola Lizard Island clade 1, AM W. 44034, dorsal view; B. Palola Lizard Island clade 1, AM W. 44146, ventrolateral view, note serrated anterior margin of mandible and length ratio between first and second peristomial ring; C. Palola Lizard Island clade 1, AM W. 44034, dorsal view of parapodia in posterior region of the fragment, arrows indicate the black pigment spots on the dorsal side of the parapodia; D. Palola Lizard Island clade 2, AM W. 44914, dorsal view; E. Palola Lizard Island clade 2, W. 44914, lateral view; F. Palola Lizard Island clade 2, AM W. 44006, lateral view. Abbreviations: cc = capillary chaetae, cf = compound falcigers, dc = dorsal cirrus of parapodium, la = lateral antenna, m = mandible, ma = median antenna, mx = maxillae, p = palps, pc = peristomial cirrus, 1 pr = first peristomial ring, 2 pr = second peristomial ring, pro = prostomium. Scale bars: A, B, F = 0.1 mm; C = 0.05 mm; D, E = 0.5 mm.