Bornella dotoides, Pola, Marta, Rudman, William B. & Gosliner, Terrence M., 2009

Pola, Marta, Rudman, William B. & Gosliner, Terrence M., 2009, Systematics and preliminary phylogeny of Bornellidae (Mollusca: Nudibranchia: Dendronotina) based on morphological characters with description of four new species, Zootaxa 1975, pp. 1-57 : 30-33

Bornella dotoides sp. nov.

( Figures 1 H, 14, 15A)

Material examined: Holotype: CASIZ 0 75831, Papua New Guinea, north coast, north of Madang, S.E. of Wongat Island, outer barrier reef, 8 mm preserved, 24 November 1990, coll: T.M. Gosliner and G.C. Williams. Paratypes: CASIZ 0 88277, Papua New Guinea, north coast, near Madang, east side “Pig Island ” [Tab Island], Barracuda Point, 6-9 m depth, two adult specimens 7 and 8 mm preserved, dissected, August 1989, coll: T.M. Gosliner. CASIZ 0 86442, Papua New Guinea, north coast, near Madang, Rasch Passage, one adult specimen 8 mm preserved, dissected, 8 June 1992, coll: T.M. Gosliner. CASIZ 174949, Papua New Guinea, barrier reef wall, one immature specimen 6 mm preserved, dissected, 14 August 1989, coll: T.M. Gosliner. CASIZ 0 75259, Papua New Guinea, north coast, near Madang, East side “Pig Island ” [Tab Island], Barracuda Point, 6 m depth, one specimen 4 mm preserved, 23 November 1990, coll: T.M. Gosliner. CASIZ 174948, Papua New Guinea, north coast, near Madang, east side “Pig Island ” [Tab Island], Barracuda Point, one specimen 6 mm preserved, 5 July 1989, coll: T.M. Gosliner. CASIZ 174951, Papua New Guinea, north coast, near Madang, Barracuda Point, one specimen 5 mm preserved, 14 January 1988, coll: T.M. Gosliner. CASIZ 174952, Papua New Guinea, north of Madang, “The Quarry”, one specimen 7 mm preserved, 12 February 1988, coll: T.M. Gosliner. CASIZ 174953, Papua New Guinea, north coast, near Madang, one specimen 4 mm preserved from Barracuda Point, one specimen 6 mm preserved from Rasch Passage, 14 February 1988, coll: T.M. Gosliner.

Etymology: The specific name refers to the shape of the dorsolateral processes, which resemble the shape of the cerata in the dendronotoidean genus Doto .

Geographic Distribution: At present this species is known only from Papua New Guinea.

External morphology: The general body shape is elongate and limaciform with the posterior end of the foot being long and tapering. The preserved adults are small, up to 8 mm in length. The body surface is covered with randomly arranged pointed tubercles ( Fig. 1 H). The general color pattern consists of a translucent whitish brown body with subepidermal white granules scattered all over ( Fig. 1 H). The head is rounded, bearing on each side of the mouth a lobe-like oral tentacle, with seven finger-like papillae of unequal length arranged in two different rows, four larger on the outer margin and three shorter on the inner side. The stalklike rhinophore sheath is tall with the rhinophore protruding at the tip. The whitish rhinophores are perfoliate with about 13 lamellae. Surrounding the upper edge of the rhinophore sheath, are three elongate anterior and anterolateral papillae and a taller, flat and branched posterior sail. The posterior sail carries three or four small papillae of different length. Posterior to the rhinophores there are four pairs of dorsolateral processes, followed by two single processes in the dorsal midline, decreasing in size towards the posterior end of the foot ( Fig. 1 H). The first and second dorsolateral processes on each side have four papillae of different sizes, those on the inner side being large than the outer two. The third dorsolateral process on each side pair has only three papillae while the fourth are simple, lacking any papillae. The first and second dorsolateral processes on each side have three bipinnate gills while the third has only two. There are no gills on the fourth dorsolateral processes. The gills are located on the inner surface, in front of the lateral papillae and in between the two main central papillae. The anus is small, located on the right side of the dorsum between the first and second pair of dorsolateral processes, closer to the second. The reproductive opening is located on the right side, midway between the rhinophore sheath and the first dorsolateral process.

Alimentary Canal: The buccal bulb is relatively small. The labial cuticle is thin, with a labial armature of cuticular rodlets at the opening into the buccal bulb. The rodlets are elongated but not as dense or numerous as in other species of the genus ( Fig. 14A ). The jaws are roughly oval in shape, without a distinct masticatory process ( Fig. 14B ). The radular formulae are 20 x 6.1. 6, 21 x 7.1. 7 and 18 x 7.1. 7 in three specimens dissected (CASIZ 0 88277, 8 mm preserved; CASIZ 0 86442, 8 mm preserved; CASIZ 174949, 6 mm preserved; respectively). The rachidian teeth are much higher than wider, with six very strong denticles on either side of a strong central cusp ( Figs. 14C,D ). The denticles increase in size away from the cusp. The blade-like laterals have a long base and pointed tip. They increase in size outwards but the outermost is a little bit shorter ( Fig. 14C ). A long unpaired oral gland is found ventrally. It extends back from the ventral midline side of the mouth to the region of the reproductive system. The paired, compact, salivary glands are yellowish in preservative, and attached along the sides of the oesophagus. They open into the posterior buccal bulb on each side of the oesophageal opening. The oesophagus is relatively short and wide, leading back to the thin walled stomach. The two anterior digestive glands open on the upper surface of the stomach. These two digestive glands are both bi-lobed and similar in size, with the lower lobe in each case connecting to the respective anterior-most dorso-lateral process, while the elongate upper lobe in each case, runs forward into the rhinophore sheaths extending as far as the posterior sail. These branches can be seen through the transparent body wall. The posterior portion of the digestive gland opens into the stomach ventrally. The posterior stomach is armed with about 20 longitudinal rows of chitinous brown spines ( Fig. 14E ). These spines are elongate and spatuliform at the upper tip. From the stomach the short intestine descends to the ventral side and then bends dorsally to the anus.

Reproductive system: ( Fig. 15A ) The ovotestis consists of three rounded or somewhat pyriform follicles lying over the posterior digestive gland. From each of these lobes a thin-walled duct connects to the hermaphrodite duct which runs around the left side of the stomach before expanding into the swollen ampulla lying on the dorsal side of the female gland mass. Shortly beyond the ampulla, the hermaphrodite duct divides into an oviduct and vas deferens. The visible oviduct is extremely short, disappearing almost immediately into the female gland mass. The vas deferens is relatively short but wide and folded, the duct covered in a uniform layer of prostate gland. The penial complex is similar to that of B. hermanni with a large fleshy lobe, armed with a single row of chitinous hooks arrange in a circle ( Fig. 14F ). A medium-sized distal pyriform allosperm receptacle opens directly to the genital aperture through an elongate duct.

Remarks: Bornella dotoides can readily be distinguished from other members of the genus by its light brownish body with opaque white spots. Bornella dotoides is relatively small in size and has pointed tubercles randomly distributed on the body. The rachidian teeth are very distinctive with very strong denticles on either side of the central cusp. Eliot (1904:103) described one specimen of Bornella excepta from the East Coast of Zanzibar, and noted that its cerata resembled ‘those of Doto in general appearance’, so it is necessary to compare it with Bornella dotoides , which is named for that very feature. Another similarity is the penial armature in both species. However they differ in the morphology of the radular teeth with B. excepta having many smaller denticles on the central tooth. The similarities of B. dotoides with B. pele sp. nov. are discussed in the remarks of the latter species.

Figures

FIGURE 1. Living animals. A – B, Bornella stellifer (Adams and Reeve in Adams, 1848); A, Malaysia, Malay Peninsula, South China Sea, Photo: T. M. Gosliner. B, Papua New Guinea, north coast, Madang, Photo: R. C. Willan. C – D, Bornella calcarata Mörch, 1863; C, Brazil, Photo: C. M. Cunha. D, Guarapi, Espiritu Santo, Brazil, Photo: J. P. Cauduro Filho. E, Bornella sarape Bertsch, 1980, Pacific coast of Mexico, Photo: A. Hermosillo. F, Bornella anguilla Johnson, 1984, Japan, Ryukyu Island, Okinawa, Photo: R. F. Bolland. G, Bornella irvingi Edmunds and Preece, 1996, Pitcairn Islands, Photo: J. Jamieson. H, Bornella dotoides sp. nov. Papua New Guinea, north Madang, “ The Quarry ”, Photo: T. M. Gosliner.

FIGURE 14. A – F, Scanning electron micrographs of Bornella dotoides new species. A, Rodlets of the labial cuticle (CASIZ 0 88277, scale bar: 8 Μm). B, Jaws (CASIZ 0 86442, scale bar: 50 Μm). C, Left half-rows of radular teeth (CASIZ 0 86442, scale bar: 8 Μm). D, Rachidian tooth (CASIZ 0 86442, scale bar: 4 Μm). E, Posterior chamber of the stomach showing spines (CASIZ 174949, scale bar: 50 Μm). F, Penis (CASIZ 0 86442, scale bar: 60 Μm).

FIGURE 15. A – E, Drawings of reproductive systems of Bornella spp. and Pseudobornella orientalis. A, Bornella dotoides sp. nov. (CASIZ 088277). B, B. pele sp. nov. (CASIZ 086356). C, B. valdae sp. nov. (AM C. 379068). D, B. johnsonorum sp. nov. (CASIZ 175406). E, Pseudobornella orientalis (CASIZ 174988). Scale bar = 1 mm. Abbreviations: am, ampulla; fglm, female gland mass; ga, genital atrium; hd, hermaphrodite duct; pr, prostate; rs, distal allosperm receptacle; va, vagina; vd, vas deferens.