Odonotoglaja mosaica, Gosliner, 2011

Gosliner, Terrence, 2011, Six new species of aglajid opisthobranch mollusks from the tropical Indo-Pacific, Zootaxa 2751 (1), pp. 1-24 : 18-22

publication ID	https://doi.org/ 10.11646/zootaxa.2751.1.1
persistent identifier	https://treatment.plazi.org/id/394D87A1-FFED-235F-FF5E-FB27FF096EE5
treatment provided by	Felipe
scientific name	Odonotoglaja mosaica
status	sp. nov.

Treatment

Odonotoglaja mosaica n. sp.

( Figures 1G, H View FIGURE 1 , 11–12 View FIGURE 11 View FIGURE 12 )

Odontoglaja guamensis Koretz, 2005c View in CoL ; Ogden, 2005; Rudman, 2005b, misidentifications.

Odontoglaja sp. 1 Gosliner et al., 2008: 38, bottom photo.

Material examined. Holotype: CASIZ 173402 , 15 m depth, NE Point of Nosy Kalakajoro, Radama Islands, Madagascar, 13.916819°S 47.760336° E, 20 October 2005, T. M. Gosliner GoogleMaps . Paratypes: CASIZ 073539 , one specimen, 3m depth, La Crique, Ile Saint Marine, Madagascar, 16.867978°S 49.901964° E, 8 April 1990 GoogleMaps , T.M. Gosliner. CASIZ 173419 , two specimens, one dissected, W of Nosy Valiha , Radama Islands, Madagascar, 14.158167°S 47.648833° E, 21 October 2005 GoogleMaps , T.M. Gosliner. CASIZ 173415 , one specimen, dissected, NW of Nosy Kalakajoro , Radama Islands, Madagascar, 13.894154°S 47.687500° E, 22 October 2005 GoogleMaps , T.M. Gosliner. CASIZ 173417 , two specimens, one dissected, W of Nosy Valiha , Radama Islands, Madagascar, 14.174952°S 47.709251° E, 20 October 2005 GoogleMaps , T.M. Gosliner. CASIZ 175943 , one specimen for shell and molecular study, 15m depth, NE Point of Nosy Kalakajoro , Radama Islands, Madagascar, 13.916819°S 47.760336° E, 20 October 2005 GoogleMaps , T.M. Gosliner.

Comparative material of Odontoglaja guamensis: CASIZ 069738, one specimen, dissected, 25 m depth, north reef north of "Pig Island" ( Tab Island ), Madang, Papua New Guinea, 24 August 1989. M. Gosliner. CASIZ 069738 , one specimen, dissected, 10 m depth, Daphne's Reef , between Wongat Island and Sinub Island, Madang, Papua New Guinea, 26 July 1989, T. Gosliner. CASIZ 175764 , sampled for molecular studies, 10 m depth, Ligpo Point, Balayan Bay, Batangas Province, Luzon Island, Philippines, 9 May 2001, T. Gosliner. CASIZ 175944 , one specimen, portion of foot removed for molecular study, 22 m depth, Pineapple Point and Nudi wall, Pulau Tenggol, Malaysia, 30 September, 2007, D. W. Behrens.

Geographic range. This species is known from Madagascar ( Gosliner et al. 2008) and South Africa ( Ogden 2005). Specimens from the Red Sea ( Koretz 2005c, Schrödl personal communication) likely represent this species as well.

Etymology. The name “mosaica” comes from Latin mosaic, referring to the reticulated pattern on the body appearing like a pattern of tiles.

Natural history. This species is found on shallow to moderately deep reefs where it is generally found under coral rubble in 3–22 m depth. No observations of feeding have been observed in the field, but one specimen dissected in this study had the entire crop filled with benthic copepods, on which it presumably feeds.

Description. External morphology. The general body color of the living animal ( Fig. 1G, H View FIGURE 1 ) is white to cream. The anterior portion of the cephalic shield, the entire length of the parapodia and the posterior end of the posterior shield, including its posterior extensions, have a reticulated network of orange lines that form a mosaic-like pattern. In the center of each of these reticulations is a yellow spot. On the posterior portion of the cephalic shield and on the anterior portion of the posterior shield, where reticulations are absent, there are small, scattered orange spots. On the cephalic shield four brown spots are present that form a diamond-shaped pattern. A single brown patch is also present on each parapodium.

The living animals are elongate and narrow, 10–15 mm in length and 3–5 mm wide. The anterior end of the cephalic shield is blunt, angular and relatively narrow. It widens more posteriorly and again narrows to a rounded posterior termination. The posterior shield is also rounded anteriorly and terminates in a curved shelf. The left lateral posterior lobe of the posterior shield is elongate and wide, terminating in an acute apex. The right posterior lobe is short, triangular and acutely pointed. The parapodia are wide covering all of the cephalic and posterior shields near the middle of the animal. The gill is plicate with 3–5 primary folds.

Shell ( Fig. 11A, B View FIGURE 11 ). The shell is relatively thickly calcified and is a shiny white. It occupies the posterior third of the posterior shield. There is a broad anteriorly-directed wing and an elongate extension that is deeply embedded in the posterior shield right to the end of the right posterior lobe.

Digestive system ( Fig. 11C, D View FIGURE 11 ). The buccal mass is large, highly muscularized, occupying the anterior twothirds of the cephalic shield ( Fig. 11C View FIGURE 11 ). The buccal bulb contains a well-developed radula. The radular formula in two specimens examined was 36 x 1.0.1. (CASIZ 173415) and 29 x 1.0.1. (CASIZ 173417). The inner lateral teeth are broad with a sloping base. On the inner side of the tooth, near the middle of its length, is a short triangular denticle. The apex of the tooth bears a bifid apex with two distinct cusps. The inner cusp is longer than the outer one. Anterior to the buccal mass are a large ventral oral gland and a smaller dorsal one. At the posterior end of the buccal mass, near the junction with the crop, is a pair of elongate salivary glands ( Fig. 11D View FIGURE 11 ). The crop is bilobed with a thin-walled anterior section that contained benthic copepods in one specimen (CASIZ 173415). The posterior portion is highly muscularized and contains thickened transverse areas that appear to be chitinous. The crop narrows posteriorly and enters the digestive gland. The intestine emerges from the right side of the digestive gland and terminates near the posterior end of the body near the base of the gill.

Central nervous system ( Fig. 11E View FIGURE 11 ): The circumesophageal nerve ring consists of paired cerebral, pedal and pleural ganglia and a single supraintestinal ganglion on the right side. The cerebral and pedal commissures are both moderately long with some degree of separation between the cerebral ganglia and the pedal ganglia. Immediately adjacent and posterior to the right pleural ganglion is the supraintestinal ganglion. From its posterior end is the right branch of the visceral loop and the osphradial nerve. The two lateral branches of the visceral loop join posteriorly at the posterior ganglia. The left visceral loop enters the subintestinal ganglion, while the right lateral nerve enters near the middle of the visceral ganglion. The visceral ganglion is larger than the subintestinal ganglion. From the visceral ganglion is the genital nerve, which lacks a distinct genital ganglion.

Reproductive system ( Fig. 11D, E–H View FIGURE 11 ). The arrangement of reproductive organs is monaulic ( Fig. 11D View FIGURE 11 ). From the large ovotestis, which is intermingled with the digestive gland, emerges the highly convoluted ampulla. The ampulla narrows into the hermaphroditic duct, which around the receptaculum seminis and enters short, coiled albumen and membrane glands with a single branch to these glands. The larger mucous gland is tightly coiled with a massive primary lobe. The ampulla then joins the duct of the short receptaculum seminis and continues to the genital atrium where it joins the duct of the bursa copulatrix. The bursa is large and spherical. Its duct is narrow and elongate and does not widen at the genital atrium. From the genital atrium the open, ciliated sperm groove leads to the cephalic penis. The penis is in similar in shape in both specimens examined ( Fig. 11G–H View FIGURE 11 ), but consists of a penial sac and a short lobed prostate gland that is joined to the penial sac by a wide duct. An anterior retractor muscle is connected at the junction of the prostate and the penis and curves anteriorly. From the posterior end of the prostate a second retractor muscle extend posteriorly and connects to the body wall. Within the penial sac is a short penial papilla that is smooth and bifid, dividing into two lobes at the apex. The penial papilla is devoid of any armature.

Remarks. Following his original description of Odontoglaja guamensis ( Rudman 1978) , Rudman (2005b) considered specimens from southern Africa as being conspecific with O. guamensis . All the specimens from the western Indian Ocean that I describe here as O. mosaica ( Rudman 2005b; Gosliner et al. 2008; present study) have a distinct pattern of orange reticulations that surround yellow spots that are distinct from the specimens of O. guamensis from the western Pacific. In O. guamensis , the body color is whitish with rounded white tubercles each with a pink or brownish center. Fine brown spots are scattered over the notum and additional brown patches may be present to varying degrees. Odontoglaja guamensis never has the orange reticulate markings found in O. mosaica , while O. mosaica never has the prominent tubercles found in O. guamensis . In O. mosaica the anterior end of the head is flat and angular, while in O. guamensis it is simply rounded. Both species are similar in size ranging in length from 10–11 mm. Specimens of the same size of the two species were dissected in this study.

The remainder of the external anatomy of the two species is quite similar. Both species have an elongate left posterior extension of the posterior shield and a short right one. Internally, the two species are also quite similar. The shell in both specimens is similar in shape ( Rudman 1978: fig. 1b; present study, Fig. 11B View FIGURE 11 ). Both species have radular teeth with bifid cusps and a triangular basal denticle ( Fig. 12 View FIGURE 12 ) and a crop that has a membranous anterior section and a muscular posterior one. The central nervous system of O. guamensis was not described by Rudman, but the arrangement of ganglia is identical to that found in O. mosaica (present study). The most significant internal difference is the structure of the penis complex. The penis of O. guamensis was not described in detail nor illustrated, but was examined in two specimens in the present study ( Figs. 11I, J View FIGURE 11 ). In O. guamensis the prostate is about the same size as the penial sac, while in O. mosaica ( Figs. 11G, H View FIGURE 11 ) it is much shorter than the penial sac. Within the penial sac, the penial papilla of O. guamensis occupies most of the sac and is broad, muscular and paddle-shaped, being dorsoventrally flattened. In O. mosaica , the penial papilla is limited to the posterior quarter of the penial sac and consists of a bifid, less well-developed papilla.

Two specimens of O. guamensis , one from the Philippines (CASIZ 175764) and one from Malaysia (175944) were sequenced for the H3 nuclear gene together with one specimen of O. mosaica from Madagascar (CASIZ 175943). The two specimens of O. guamensis differed by 0.8 % in the H3 gene, while the specimen of O. mosaica differed from these two specimens of O. guamensis by 2.9% and 3.5% respectively. These molecular data further support the anatomical data that O. mosaica and O. guamensis represent distinct species.