- Rediscovery of Talehsapia annandalei (Polychaeta: Pilargidae) in Songkhla Lagoon, Thailand1
The pilargid polychaete Talehsapia annandalei Fauvel, 1932, has been rediscovered in its type locality and its taxonomic affinities are clarified. The genus is set off from remaining synelmins based on possession of palps completely fused and absence of tentacular cirri. The "jawlike" structure is rather a symmetrical, discontinuous pair of denticulated bands and is not a true jaw.
Fauvel (1932) described the polychaete Talehsapia annandalei based on two specimens collected in Taleh-Sap, Thailand (Taleh-Sap means the Songkhla inner sea or lagoon). The taxonomic affinity of this taxon was enigmatic because of the presence of atypical "jaws" and the species was originally regarded as incertae sedis; it did not seem to belong to any of the then known polychaete families and it was regarded, questionably, as a very aberrant eunicid. In a later monograph Fauvel (1953) retained it as incertae sedis but closely allied to Hesionidae and more specifically related to what we now call pilargids. However, Fauvel did not accept the Pilargidae as an independent family. Hartman (1947), in contrast, did regard Pilargidae as an independent family and included Talehsapia Fauvel in her revision, but for her it was a little-known genus closely allied to Loandalia Monro. In her remarks, she commented that Talehsapia differs from Loandalia in the lack of palps and the presence of jaws. This affinity with Loandalia had already been stated by Fauvel (in Mesnil and Fauvel 1939:39-40) after he rejected its original apparent affinity with euniceans and placed the genus in the Hesionidae.
In her revision of the Pilargidae, Pettibone (1966) questionably regarded Talehsapia as a junior synonym of Loandalia. Fauchald (1977:78-79) kept the taxon as incertae sedis because of its atypical jaws and even rejected, following Emerson and Fauchald (1971), its recognition as a pilargid. This problematic genus was included in the Pilargidae but regarded as being different from other pilargids by Salazar-Vallejo (1987, Salazar-Vallejo and Solís-Weiss 1992) on the basis of lack of palps and presence of jaws. Licher and Westheide (1994:225-226) thought that this genus is a member of the Pilargidae.
The original description was published 70 yr ago, and until now, no new specimens have been available to clarify this situation. The second record of Talehsapia (Fauvel 1935) should be ascribed to Loandalia, as Fauvel himself indicated (in Mesnil and Fauvel 1939:39-40). The original specimens may be lost; in fact, several letters are still without reply from Indian colleagues, and the loss of these specimens has yet to be confirmed. We examined the single slide deposited in the collections of the Université Catholique de l'Ouest, Angers, and herein we present an analysis of the enigmatic features of this species on the basis of six additional specimens collected by one of us (S.A.). The pharynx has [End Page 267] one pair of anterolateral glandular areas; internally, at the same level, there is a unique reinforcement structure that might explain the jawlike resemblance noted by Fauvel in the original description. The dorsal spine starts on setiger 8, ventral cirri start on setiger 4, and the pharynx can be 5-7 setigers in length. In most other features, the original description by Fauvel (1932) is fairly complete.
Materials and Methods
All six specimens were collected by S.A. on 8 August 1998 in the Songkhla Lake (lagoon) (7° 29´ 17˝ N, 100° 24´ 34˝ E). Sediments were sampled using a Tamura's grab (Rigosha Co., Japan, 0.05 m2) at 0.5-m water depth and were mainly silty-clay or silty-clay loam. Water salinity was 24 psu (range 0-24 psu), water temperature was 33°C, dissolved oxygen was 7.7 mg/liter, and pH was 7.1. The anterior region of two specimens was dissected to remove the pharynx; one pharynx was cross-sectioned close to the anterior end and the other was cut longitudinally. Reference materials are deposited in the following collections: Museum National d'Histoire Naturelle, Paris; The Natural History Museum, London; collections of the Prince of Songkla University, Hat...