Chelidonura mandroroa, Gosliner, 2011

Gosliner, Terrence, 2011, Six new species of aglajid opisthobranch mollusks from the tropical Indo-Pacific, Zootaxa 2751 (1), pp. 1-24 : 12-15

publication ID	https://doi.org/ 10.11646/zootaxa.2751.1.1
persistent identifier	https://treatment.plazi.org/id/394D87A1-FFF7-2344-FF5E-FC6EF9DB6FE6
treatment provided by	Felipe
scientific name	Chelidonura mandroroa
status	sp. nov.

Treatment

Chelidonura mandroroa View in CoL n. sp.

( Figures 1E View FIGURE 1 , 2C View FIGURE 2 , 8 View FIGURE 8 , 9 View FIGURE 9 )

Chelidonura sp. 1 Gosliner et al. 2008: 46, bottom figure.

Chelidonura sp. De Ponti, 2009; Chen, 2009.

Philinopsis sp. 1 Rudman, 2001 .

Philinopsis sp. Behrens, 2005 .

Material examined. Holotype: CASIZ 173595 , not dissected, 11m depth, wall and reefs flat west of Nosy Valiha , Radama Islands, Madagascar, 14.15829° S 47.648473° E, 15 October 2005, T. M. Gosliner GoogleMaps . Paratype: CASIZ 182002 , dissected, molecular sample taken from foot, 13 m depth, wall and reefs flat west of Nosy Valiha , Radama Islands, Madagascar, 14.15829° S 47.648473° E, 15 October 2005 GoogleMaps , T. M. Gosliner . Paratype: CASIZ 112290 , not dissected, Manado , Sulawesi, Indonesia, April 1988, Pauline Fiene and Mike Severns .

Geographic range. This species is known only from Japan ( Nakano 2001), Taiwan ( Chen 2009) Indonesia, Philippines ( Gosliner et al. 2008) Tanzania ( de Ponti 2009) and Madagascar (this study).

Etymology. The name mandroroa is the Malagasy word meaning to hallucinate. This refers to the striking, psychedelic color pattern that characterizes this species.

Natural history. This species is found on shallow reef flats, often under coral rubble or crawling in the open at 8–13 m depth.

Description. External morphology. The general body color of the living animal ( Fig. 1A View FIGURE 1 ) is dark brown to black with burnt orange patches and circles each bordered by bright yellow. This pigment pattern is found on the cephalic and posterior shields, the parapodia and the foot. The living animals are elongate, and narrow. The anterior end of the cephalic shield is trilobate. The cephalic shield is triangular, broadest anteriorly and terminates posteriorly with a short rounded lobe. The posterior shield is well rounded anteriorly and terminates in two short, broad posterior lobes that are acutely pointed at their ends. They are approximately equal in length. The parapodia are relatively wide, largely covering most of the cephalic and posterior shields. The gill is plicate with 11 primary folds.

Shell ( Fig. 2C View FIGURE 2 , 8A View FIGURE 8 ). The shell is relatively thickly calcified and is a shiny white with a brownish tinge. It occupies the left third of the posterior shield. There is a broad anteriorly-directed wing and an elongate extension that is deeply imbedded in the posterior shield right to the end of the right posterior lobe.

Digestive system ( Fig. 8B View FIGURE 8 ). The buccal mass is small, highly muscularized, occupying the anterior two-thirds of the cephalic shield. The buccal bulb entirely lacks any vestige of a radula. There is a small dorsal oral gland and a large ventral one. At the posterior end of the buccal mass, near the junction with the crop, is a pair of elongate salivary glands. The crop is small and saccate, about the same width as the buccal bulb. 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. 8C View FIGURE 8 ): The circumesophageal nerve ring consists of paired cerebral, pedal, pleural ganglia and a single supraintestinal ganglion on the right side. The cerebral and pedal commissures are both short with poorly separated 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 the visceral ganglion posterior to its junction with the subintesinal 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. 8D, E View FIGURE 8 , 9 View FIGURE 9 ). The arrangement of reproductive organs is a modified monaulic arrangement( Fig. 8D View FIGURE 8 ). From the large ovotestis, which is intermingled with the digestive gland, emerges the convoluted ampulla. The ampulla narrows into the hermaphroditic duct, which curves around the receptaculum seminis and enters short, coiled albumen and membrane glands. It appears to have only a single entrance to these glands. Immediately prior to curving around the receptaculum, the hermaphroditic duct has a swollen, bulbous portion. The larger mucous gland is curved with a massive primary lobe. The hermaphroditic duct 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 short and widens slightly at the genital atrium. From the genital atrium the open, ciliated sperm groove leads to the cephalic penis. The penis ( Fig. 8E View FIGURE 8 , 9 View FIGURE 9 ) consists of a penial sac and a lobate prostate gland that is joined to the penial sac by a wide duct. Within the penial sac is a large penial papilla that is smooth and conical. Extending from the apical end of the penial papilla is a small curved, apical stylet ( Fig. 9C View FIGURE 9 ).

Remarks. Rudman (2001) suggested that this species was likely a species of Philinopsis based on the shape of its head, but later suggested it may be a species of Chelidonura ( Rudman 2002) . He also suggested that it likely had a tubular buccal bulb. Species of Philinopsis have either a rounded or quadrangular anterior end of the cephalic shield rather than the distinctly lobate one found in the present species. The head of C. mandroroa is similar in shape to that of C. inornata Baba, 1949 ; C. electra Rudman, 1970 , C. castanea Yonow, 1994a ; C. punctata Eliot, 1903 and C. amoena Bergh, 1905 , (see Gosliner et al. 2008). Several other anatomical features support the placement of this species in Chelidonura . The shell is completely calcified with a broad anteriorly directed wing. The buccal mass is muscular but relatively small. The central nervous system has short cerebral and pedal commissures. The reproductive system has a distal receptaculum seminis and a single lobe of the mucous gland. In contrast, species of Philinopsis have a shell without a calcified expanded anteriorly-directed wing ( Fig. 2C View FIGURE 2 , 8A View FIGURE 8 ), a central nervous system with elongate commissures, a bilobed mucous gland and receptaculum seminis with an elongate duct.

A preliminary molecular phylogenetic analysis (Gatdula et al. personal communication) using the H3 nuclear gene fragment has this species clustered as sister taxon to Chelidornura inornata . More detailed analysis is required using multiple genes, but preliminary data strongly indicate that this species is nested within the clade of Chelidonura species.

Chelidonura mandroroa can be clearly distinguished from all other alglajids by its unique color pattern of a black body with orange patches surrounded by yellow lines. The shape of the anterior portion of the body is most similar to C. inornata , C. electra , C. castanea , C. punctata and C. amoena , but all of these species have elongate posterior extensions of the posterior shield, while C. mandroroa has short ones. Chelidonura mandroroa is the only species of Chelidonura that has been described with an apical cuticular stylet on the penis. The distinctive color pattern, lobed head with short posterior extensions of the posterior shield and the cuticular apex of the penis are all unique and distinctive attributes of this species.