Bornella sarape Bertsch, 1980

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 : 23-26

Bornella sarape Bertsch, 1980

( Figures 1 E, 4D, 12)

Bornella sarape Bertsch, 1980: 33 –42, figs. 1–11.

Material examined: LACM 36-71, Mexico, Gulf of California, Isla Partida, off White Rock, 28.55.5'N, 113.05.6'W, 0 8 March 1936, one adult specimen 25 mm preserved, dissected, 82 m depth, coll: R/V Velero III ( AHF 557-36). LACM 40-53, Mexico, Gulf of California, North of Isla Partida, 28.56.2'N, 113.02.6'W, 0 5 February 1940, one adult specimen 25 mm preserved, dissected, 84–139 m depth, coll: R/V Velero III ( AHF 1081-40). LACM 14801, Mexico, Jalisco, Melaque, January 1976, one immature specimen 11 mm preserved, dissected, intertidal, coll: Forest & Roy Poorman. LACM 24996, Mexico, Sonora, San Carlos Bay, trailer park, October 1976, five adult specimens 15, 15, 16, 17 & 17 mm preserved, two dissected, intertidal, coll: Forest & Roy Poorman. LACM 25007, Mexico, Sonora, Guaymas, San Carlos Bay, Honeymoon Island, diving on Padina, 1976 , one adult specimen 20 mm preserved, dissected, coll: R. Poorman & Shy.

Distribution: From Mexico, Gulf of California to Bahia Banderas, and Panama ( Bertsch 1980; Bertsch & Kerstitch 1984; Hermosillo et al. 2006).

External morphology: The general body shape is elongate and limaciform with the posterior end of the foot being long and tapering ( Fig. 1 E). The living adults reach to 40 mm in length ( Hermosillo 2002). The general color pattern is pale yellow-brown, with dark brown to black reticulate pattern, which sometimes coalesces into dark patches. The dorsolateral processes and rhinophore sheaths have the same coloration ( Fig. 1 E). A medio-dorsal ridge extends lengthwise down the animal’s body. The ridge is broken into two sections. The short anterior section runs from just in front of the first pair of dorsolateral processes, forward to just behind the rhinophore sheaths where it forks, with a branch going to the base of each rhinophore. The long posterior section of the ridge runs from just behind the first pair of dorsolateral processes back to the tip of the foot. Anteriorly this ridge also forks, this time with a branch going out to each of the first pair of dorsolateral processes. On either side of the mouth is an oral lobe, bearing nine-ten papillae arranged in two rows, four smaller papillae at the base of five-six larger ones. There is a pair of large, conical perfoliate rhinophores, each bearing about 19 lamellae; completely retractile into elevated rhinophoral sheaths. Each rhinophore is nestled in a large, flattened rhinophoral sheath, into which it is able to completely retract. The rhinophore sheaths have a tall, slightly laterally compressed stalk from which the rhinophore protrudes. One anterior and two anterolateral finger-like papillae, as well as a taller, quite elaborate posterior structure which looks quite similar in shape to one of the dorsolateral processes, surround each rhinophore, at the upper edge of its stalk. Posterior to the rhinophores are three pairs of dorsolateral five branched processes, followed by three-four small, single processes arranged along the dorsal midline. The translucent gills on each dorsolateral process are inserted at the junction of the main stalk and the branches. There are three well-developed, nonretractile, tripinnate gills per dorsolateral process. The reproductive opening is located on the right side, midway between the rhinophore sheath and the first dorsolateral process. The anus is smaller and it is located on the right side of the dorsum between the first and second pair of dorsolateral processes, closer to the second. The sole of the foot is narrow and pale yellow in color.

Alimentary Canal: The buccal bulb is relatively large. The labial cuticle is thick, and consists of elongate and numerous overlapping scales, arranged in fairly regular rows ( Fig. 12A ). The jaws are roughly oval in shape, without a distinct masticatory process ( Fig. 12B ). The radular formulae of some of the specimens dissected are: 37 x 21.1.21 (LACM 25007, 20 mm preserved), 35– 37 x 13.1.13 (LACM 36-71, 25 mm preserved; LACM 24996, 17 mm preserved), 30– 33 x 10– 11.1.10 –11 (LACM 24996, 17 mm preserved; LACM 14801, 11 mm preserved). The rachidian teeth are higher than wider ( Figs. 12D,E ). They lack well-developed denticles on each side of the large cusp but have a number of irregular faint denticles at the posterior base of the cusp ( Figs. 12F ). Most of the specimens examined have from 10 to 13 laterals ( Fig. 12D ), but in one specimen (LACM 25007) the number rises to 21 ( Fig. 12E ). The laterals are all blade-like, increasing outwards but always the two or three outer laterals a little bit shorter ( Figs. 12D,E ). A long unpaired oral gland is found ventrally ( Fig. 12C ). It opens on the mid-ventral side of the mouth and runs back to the region of the reproductive system. A pair of yellowish, elongate and highly branched salivary glands is attached to the posterior side of the oesophagus. The oesophagus is short and wide. The two anterior digestive glands open on the upper surface of the stomach. Both glands are large and elongate but the gland on the right is larger than the left one. They each have a single branch that runs to their respective anterior dorsolateral process. The posterior lobe of the digestive gland opens on the lower left surface of the stomach. All pairs of dorsolateral processes, behind the first pair, receive branches from the posterior portion of the digestive gland. The posterior chamber of the stomach is tubular and armed, in its anterior part, with about 20 to 25 longitudinal rows of chitinous brown spines. These spines are elongate, straight and rounded at the tip ( Fig. 12G ). From the stomach the short intestine descends to the ventral side and then bends dorsally to the anus.

Reproductive system: ( Fig. 4D ): The ovotestis consists of between five and eight closely packed, rounded or somewhat pyriform follicles lying over the posterior digestive gland and each follicle is joined to the hermaphrodite duct by a fine tube. The hermaphrodite duct runs around the stomach on the left side and expands into the large C-shaped ampulla on the dorsal side of the female gland mass. From the ampullar region the narrow hermaphrodite duct divides, giving rise to the separate oviduct and vas deferens. The visible oviduct is very short before it disappears into the female gland mass. The vas deferens is relatively long and coiled, and appears to have a layer of prostate gland tissue along its entire length. The large elongate penial bulb lacks any recognizable penial papilla, and no traces of penial armature were found in any of the specimens dissected. A small distal pyriform allosperm receptacle opens at the genital aperture through a long duct.

Remarks: Bornella sarape is known from several specimens from the Pacific coast of Mexico and Panama ( Bertsch 1980; Bertsch & Kerstitch 1984; Hermosillo et al. 2006). The external anatomy, coloration and radula described by the previous authors agree with those of our specimens, except for the presence of a constant number of three pairs of branching dorsolateral processes, and the presence of tripinnate gills, which have been previously recorded as uni- or bi-pinnate. The reproductive system is described here for the first time. The colour pattern of this species clearly distinguishes it from other species of Bornella . The pale yellow body with its brown reticulate pattern distinguishes it from the species described from the Pacific and the Caribbean, which have orange or reddish reticulations. Internally the main distinguishing features are that the penis lacks a distinct papilla and is unarmed and the rachidian tooth has many irregular and faint denticles at the base of the median cusp. Also the rounded tips of the stomach spines are more similar to those of B. anguilla than to the other species, but in B. anguilla they are more numerous.

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 12. A – G, Scanning electron micrographs of Bornella sarape Bertsch, 1980. A, Rodlets of the labial cuticle (LACM 24996, scale bar: 100 Μm). B, Left jaw (LACM 24996, scale bar: 100 Μm). C, Oral gland (LACM 25007, scale bar: 100 Μm). D, Half radula (LACM 24996, scale bar: 10 Μm). E, Right half-rows of radular teeth (LACM 25007, scale bar: 20 Μm). F, Lateral view of the rachidian tooth (LACM 24966, scale bar: 10 Μm). G, Stomach spines (LACM 24966, scale bar: 100 Μm).

FIGURE 4. A – E, Drawings of reproductive systems of Bornella spp. A, Bornella stellifer (CASIZ 075076). B, B. calcarata (CASIZ 118665). C, B. hermanni (AM C. 113793). D, B. sarape (LACM 24996). E, B. anguilla (CASIZ 173389). Scale bar = 1 mm. Abbreviations: am, ampulla; fglm, female gland mass; hd, hermaphrodite duct; p, penis; pb, penial bulb; pr, prostate; rs, distal allosperm receptacle; va, vagina; vd, vas deferens.