Hypselodoris saintvincentius Burn, 1962

Johnson Aângel Valdeâs, Rebecca F., 2001, complex (Mollusca, Nudibranchia, Chromodorididae), with remarks the genus Brachychlanis Ehrenberg, 1831, Journal of Natural History 35 (9), pp. 1371-1398 : 1390-1393

Hypselodoris saintvincentius Burn, 1962

(®gures 1D, 10C, 13±14)

Hypselodoris saintvincentius Burn, 1962: 151 ±152, ®gures 1, 2, pl. 1, ®gures 1, 2. Hypselodoris infucata (RuÈppell and Leuckart) : Wells and Bryce, 1993: 114, ®gure 139.

Material examined

Rocky Head, SW Enderby Island, Dampier Archipelago, Perth , Western Australia, 4 May 1987, two specimens 15±28 mm long, leg. C. Bryce and F. Wells ( WAM 187 ±87). D9 wreck, Cockburn Sound, south of Perth , Western Australia, 25 December 1998, four specimens 16±28 mm long, leg. S. Fahey ( CASIZ 115232 ) .

Distribution

This species is found exclusively in southern and temperate western Australia. It was originally described by Burn (1962) from Coobowie, Gulf of St. Vincent, and has subsequently been recorded from the Dampier Archipelago, Perth, Western Australia (C. Bryce, personal communication).

External morphology

The living animals are up to 60 mm in length. The body is elongate and relatively high in pro®le (®gure 1D). The general body colour is blue or greenish blue. Dark blue and oOE-white spots are scattered over the dorsum and the posterior end of the foot. There are no yellow spots. A large oOE-white patch extends from the rhinophores to the gills down the centre of the dorsum. This slightly raised, beige area can extend in irregular projections towards the edges of the mantle. The posterior end of the foot extends beyond the edge of the posterior mantle edge. There are 28 tightly packed, posterior mantle glands and 16±18 smaller glands on either side of the head (®gure 10C). The perfoliate rhinophores are composed of 8±12 lamellae. They are white, with red or reddish orange lamellae. The gill is composed of 11 unipinnate branchial leaves, which are white proximally and red distally.

Anatomy

The buccal mass is divided evenly into an anterior glandular portion and a posterior muscular one. The jaws are composed of a number of elongate, unicuspid rodlets (®gure 13D) about 20 m m in length. The radular formula is 70 Ö 81.0. 81 in a 28 mm long specimen ( CASIZ 115232 ). Rachidian teeth are absent. The innermost lateral teeth (®gure 13A) have two large cusps, with a single, shorter denticle on the inner side. The remaining lateral teeth (®gure 13B) are hook-shaped, have two cusps and lack denticles on both sides. The outer laterals (®gure 13C) are short, having four to ®ve denticles situated under the second cusp .

The reproductive system (®gure 14) has a short, oval ampulla that divides into the oviduct and the prostate. The oviduct is short and enters the female glands near the centre of the mass. The prostate is long, tightly coiled with several loops. It narrows and then expands into a long, muscular vas deferens. The ejaculatory portion of the vas deferens is long and coiled, and opens into a common atrium with the vagina. The penis is unarmed. Near the exit of the female glands there is a large, rami®ed vestibular gland. The vagina is very short and wide. Near the proximal end of the vagina the minute, oval seminal receptacle emerges. The very long and convoluted uterine duct connects to the vaginal duct between the seminal receptacle and the bursa copulatrix connections.

Remarks

Hypselodoris saintvincentius is clearly distinguishable from H. infucata and H. obscura by its external coloration. The former has a large oOE-white area in the centre of the dorsum, whereas H. infucata and H. obscura never have any whitish colour. Hypselodoris saintvincentius can reach lengths of up to 60 mm and the other two species reach only 50 mm. The mantle glands in H. saintvincentius are distributed in a similar pattern to those of H. infucata and H. obscura , but the glands in H. saintvincentius are more numerous and much more closely packed. The radular teeth are very similar. All of the innermost lateral teeth of H. saintvincentius have a small denticle, but small denticles are only present on some teeth of some specimens of H. infucata . The main anatomical diOEerence between H. saintvincentius , and H. infucata and H. obscura is found in the reproductive system. Hypselodori s saintvincentius has a short, wide vaginal duct whereas H. infucata and H. obscura consistently have longer and narrower vaginal ducts (see ®gure 15).

Phylogenetic analysis

Gosliner and R. Johnson (1999) studied the phylogenetic relationships of members of the genus Hypselodoris and demonstrated that H. infucata and H. obscura are sister taxa. However, they did not include H. saintvincentius in their analysis. In order to determine the phylogenetic relationships, and therefore the systematic position of these three species, we have used the original database of Gosliner and R. Johnson (1999) with some modi®cations. To polarize the morphological variability we have selected Chromodoris as the outgroup, represented by Chromodoris willani Rudman, 1982 , which is considered a relatively underived member of the clade ( Rudman, 1984; Gosliner and R. Johnson, 1999).

In order to develop a phylogenetic hypothesis regarding these taxa, the characters described by Gosliner and R. Johnson (1999) were placed in a data matrix ( table 1), adding the new information for H. saintvincentius . Also, the new character (60 Ð length of the ejaculatory portion of the vas deferens) was added. This new character has two states, 0: short, which is the plesiomorphic state, since it is present in Chromodoris willani , the outgroup, and 1: long, which is the apomorphic state. Data were analysed by means of Phylogenetic Analysis Using Parsimony ( PAUP) Version 4.0b2 (SwoOEord, 1993) using the heuristic algorithm. In this analysis 14 most parsimonious trees 204 steps long, with consistency indices of 0.333 and retention indices of 0.670, were obtained. A single consensus tree was produced from them.

The tree topology obtained is slightly diOEerent from that obtained by Gosliner and R. Johnson (1999) due to the inclusion of H. saintvincentius and character 60. In this new phylogeny H. infucata and H. obscura are still sister species, and H. saintvincentius is sister to them. The larger clade containing H. infucata , H. obscura and H. saintvincentius is the sister group to H. festiva (A. Adams, 1861) , and this clade is sister to H. carnea (Bergh, 1889) and H. capensis ( Barnard, 1927) (®gure 16). The remainder of the tree is basically the same as that obtained by Gosliner and R. Johnson (1999) and is not shown here.