Aphelodoris, BERGH, 1879

Valdés, Ángel, 2002, A phylogenetic analysis and systematic revision of the cryptobranch dorids (Mollusca, Nudibranchia, Anthobranchia), Zoological Journal of the Linnean Society 136 (4), pp. 535-636 : 579-585

GENUS APHELODORIS BERGH, 1879

Aphelodoris Bergh, 1879: 107–108 . Type species: Aphelodoris antillensis Bergh, 1879 , by monotypy.

Diagnosis

Body soft, lacking integumentary spicules. Dorsum smooth, with no tubercles. Anterior border of the foot grooved but not notched. Head with two large and grooved lateral prolongations. Labial cuticle lacking rodlets. Radula composed of simple, hamate teeth. The innermost teeth may be simple or denticulate. Reproductive system with a tubular, granular and simple prostate. Penis and vagina unarmed. Vestibular or accessory glands absent.

Remarks

The genus Aphelodoris was introduced by Bergh (1879) for Aphelodoris antillensis Bergh, 1879 , the type species by monotypy. According to Bergh (1879) Aphelodoris is very similar in body shape to the chromodorids, but it differs from this latter group in having a narrow mantle margin and a short posterior end of the foot. Other differences include the shape of the oral tentacles, which are grooved, and the presence of multipinnate branchial leaves. Internally the differences are even more obvious, with the absence of jaws and the presence of a single blood gland. Bergh (1879) regarded Aphelodoris as a member of the family Chromodorididae , but Odhner (see Franc, 1968) later transferred it to the family Asteronotidae .

APHELODORIS ANTILLENSIS BERGH, 1879

( FIGS 4G , 26 , 27 )

Aphelodoris antillensis Bergh, 1879: 108–113 . Doris bistellata Verrill, 1900: 548 , pl. 66, fig. 2.

Type material

The type material of Aphelodoris antillensis could not be located at ZMUC (K. Jensen, pers. comm.) and is presumed lost .

Additional material

Off ferry dock, Puerto Morelos, South of Cancún, Quintana Roo, Mexico, 28 March 1985, one specimen, 10 mm preserved length, leg. T . M. Gosliner ( CASIZ 071876 ). Burger King Reef , near Soto’s Reef , South of West Bay, Grand Cayman Island, Cayman Islands, 8 May 1991, one specimen, 18 mm long, leg. J. Hamann ( CASIZ 077289 ) .

External morphology

The background colour is translucent pale cream, with numerous opaque white, yellow and brown spots ( Fig. 4G ). The arrangement, size and abundance of these spots is extremely variable. This variability has been described and illustrated in detail by Hamann (1992). The rhinophores and gill are also translucent pale cream, having brown, yellow or opaque white spots, which vary in size and arrangement. The dorsum is smooth, bearing a few low and soft tubercles. The rhinophoral and branchial sheaths have no tubercles. There are six bipinnate branchial leaves, forming a circle. The anal papilla is situated in the centre of the branchial circle of leaves. The rhinophores are elongate, having nine lamellae in a 10-mm preserved length specimen.

Ventrally there are two large, blunt and grooved oral tentacles ( Fig. 26F ). The anterior border of the foot is grooved but not notched.

Anatomy

The posterior end of the glandular portion of the oral tube has six strong retractor muscles ( Fig. 26D ), which attach to the body wall. The oval, muscular buccal bulb has two large additional muscles attached; two long salivary glands connect with it at each side of the oesophageal junction. The buccal bulb is as long as the glandular portion of the oral tube. The labial cuticle is smooth. The radular formula is 31 ¥ 43.0. 43 in a 10-mm preserved length specimen. Rachidian teeth are absent. The innermost lateral teeth are triangular, having a long cusp with 5–6 denticles ( Fig. 27A ). The following teeth are smooth. The teeth from the middle portion of the half-row are larger than those closer to the medial portion of the radula ( Fig. 27B ). The outermost teeth are smaller and also lack denticles ( Fig. 27C ). The oesophagus is short and connects directly to the stomach.

The ampulla is very long and convoluted ( Fig. 26B ). It branches into a short oviduct and the prostate. The oviduct enters the female gland mass near to its centre. The prostate is short and flattened. It connects with a long duct that narrows and expands again into the large ejaculatory portion of the deferent duct. The muscular deferent duct opens into a common atrium with the vagina. The vagina is long. At its proximal end it joins the bursa copulatrix. From the bursa copulatrix leads another duct connecting to the uterine duct and the seminal receptacle ( Fig. 26C ). The bursa copulatrix is oval in shape, about four times as large as the seminal receptacle.

In the central nervous system ( Fig. 26E ) the cerebral and pleural ganglia are fused and distinct from the pedal ganglia. There are four cerebral nerves leading from each cerebral ganglion and two pleural nerves leading from each pleural ganglion. There is no separate abdominal ganglion on the right side of the visceral loop. The buccal ganglia are near to the rest of the central nervous system, joined to the cerebral ganglia by two relatively short nerves. Gastrooesophageal, rhinophoral and optical ganglia are present. The pedal ganglia are clearly separated, having three nerves each one. The pedal and parapedal commissures are enveloped together with the visceral loop.

The circulatory system ( Fig. 26A ) consists of a large heart and a blood gland situated behind the central nervous system.

Remarks

This common Caribbean species was described by Bergh (1879) based on several preserved specimens from St. Thomas, Virgin Islands. Ev. Marcus & Er. Marcus (1963) illustrated and described living animals for the first time. Hamann (1992) redescribed A. antillensis and synonymized it with Doris bistellata Verrill, 1900 .

Figures

Figure 4. Living animals. A, Doris pseudoargus (CASIZ 121105). B, Doris immonda (CASIZ 089023), photo by T. M. Gosliner. C, Doris granulosa (CASIZ 073536), photo by T. M. Gosliner. D, Discodoris boholiensis (CASIZ 083654), photo by T. M. Gosliner. E, Discodoris ketos, San Pedrillo, Puntarenas, Costa Rica, photo by T. M. Gosliner. F, Thordisa rubescens (CASIZ 015860), photo by T. M. Gosliner. G, Aphelodoris antillensis (CASIZ 077289), photo by T. M. Gosliner. H, Peltodoris atromaculata (CASIZ 119474). I, Peltodoris nobilis, Monterey Bay, California, photo by A. Smith.

Figure 26. Aphelodoris antillensis (CASIZ 071876). A, general view of the anatomy; scale bar = 1 mm. B, reproductive system; scale bar = 1 mm. C, detail of several reproductive organs; scale bar = 1 mm. D, lateral view of the buccal bulb; scale bar = 1 mm. E, central nervous system; scale bar = 0.5 mm. F, ventral view of the mouth area; scale bar = 2 mm.

Figure 27. Aphelodoris antillensis (CASIZ 071876), SEM images of the radula. A, inner lateral teeth; scale bar = 15 Mm. B, mid-lateral teeth; scale bar = 15 Mm. C, outer lateral teeth; scale bar = 15 Mm.