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 : 702-703

Palola Lizard Island Clade 6

( Fig. 4 )

Material examined. AM W.43782, MI QLD 2335, sequenced; AM W.43905, MI QLD 2331, sequenced and photographed; AM W.44010, MI QLD 2341, sequenced; AM W.44129, MI QLD 2356, sequenced; AM W.44192, MI QLD 2359, (2, 1 sequenced); AM W.44645, MI QLD 2410, sequenced and photographed; AM W.44330, MI QLD 2359 (2); AM W.44334, MI QLD 2371; AM W.44652, MI QLD 2413; AM W.43914, MI QLD 2337.

Description. Most specimens relatively large with strongly calcified mandibles protruding from mouth. Anterior fragments closely examined for all sequenced specimens, ranging in size from 11 mm to 50 mm, 1.5–3 mm wide; with 41 to 153 chaetigers. Dorsoventrally flattened with a deep ventral groove. Some larger fragments with branchiae, starting from chaetiger 77 (AM W.44645) to chaetiger 98 (AM W.43906). No ventral eyespots. Head and body pigmented, particularly dorsally, with fairly uniform brown pigment ( Fig. 2 A, B). Antennae, palps and peristomial cirri without pigment. Antennae and palps wrinkled, in preserved material, tapering and pointy tip. Median antenna generally reaches to chaetiger 4, lateral antennae to chaetiger 2 or 3 and palps to posterior end of first or to second peristomial ring. Tapering peristomial cirri reach forward at least to anterior margin of first peristomial ring or beyond. Eyes dark, round with a ventral notch and nestled between lateral antennae and palps. Bases of ventral cirri strongly inflated after chaetiger 10. Chaetiger 10 with single dark acicula, single capillary chaetae and multiple compound falcigers ( Fig. 4 C, D).

Remarks. This is the most morphologically distinctive of the six clades found on Lizard Island. Members of Palola clade 6 can be distinguished from the other clades by the relatively uniform dark brown pigmentation and the long peristomial cirri which often reach forward to the eyes or beyond. This clade is the most closely related to the type species of the genus, Palola viridis , but can be distinguished from it by the shorter antennae: in P. viridis , the median antenna reaches to chaetiger 10 ( Fauchald 1992) and only to chaetiger 4 in Palola Lizard Island clade 6. The average genetic divergence between the two lineages is 20% (Kimura-2-parameter model) for COI. Posterior ends are missing in all of the specimens, but even the longer fragments do not have ventral eyespots as reported in P. viridis .

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.

FIGURE 4. Palola Lizard Island clade 6. All material ethanol preserved. A. AM W. 43905, dorsal view; B AM W. 44645, dorso-lateral view. C. AM W. 44645, parapodium 10; D. AM W. 44645, parapodium 10, detail of compound falciger. Abbreviations: a = aciculum, cc = capillary chaeta, cf = compound falciger, dc = dorsal cirrus of parapodium, vc = ventral cirrus of parapodium. Scale bars: A, B, C = 0.1 mm, D = 20 µm.