Hypselodoris lacuna, Gosliner & Johnson, 2018

Epstein, Hannah E., Hallas, Joshua M., Johnson, Rebecca Fay, Lopez, Alessandra & Gosliner, Terrence M., 2018, Reading between the lines: revealing cryptic species diversity and colour patterns in Hypselodoris nudibranchs (Mollusca: Heterobranchia: Chromodorididae), Zoological Journal of the Linnean Society 20 (1), pp. 1-74 : 33-36

publication ID	https://doi.org/ 10.1093/zoolinnean/zly048
publication LSID	urn:lsid:zoobank.org:pub:F0065FD2-417C
DOI	https://doi.org/10.5281/zenodo.5980684
persistent identifier	https://treatment.plazi.org/id/411BF606-FFC2-FF9E-FC65-FED8FC9A6EC4
treatment provided by	Plazi
scientific name	Hypselodoris lacuna
status	sp. nov.

Treatment

HYPSELODORIS LACUNA GOSLINER & JOHNSON View in CoL SP. NOV.

(FIGS 2J, 13D, 18A–D, 19)

LSID: urn:lsid:zoobank.org:act:CC5531BC-6A9E- 48F3-622959E3D128

Hypselodoris View in CoL sp. 11 Gosliner et al., 2008: 270, top photograph.

Hypselodoris View in CoL sp. 20 Gosliner et al., 2015: 2639, bottom right photograph.

Type material

Holotype: NMP 0 41280 (formerly CASIZ 182758 ), s u b s a m p l e d f o r m o l e c u l a r s t u d y, B e t h l e h e m 1 3.6 7 3 2 9°N, 1 2 0.8 4 0 9 3°E, T i n g l o y, B a t a n g a s, Philippines, 17 May 2010, T. Gosliner.

Paratypes: CASIZ 208587 , one specimen, dissected, Coral Cove , 13.51664°N, 120.99176°E, Puerto Galera, Mindoro Oriental, Philippines, 31 March 2015, P. J. Aristorenas GoogleMaps . CASIZ 208188 , one specimen, tissue removed for molecular study, Batangas Channel , 13.5199°N, 120.9604°E, Puerto Galera, Mindoro Oriental, Philippines, 12 April 2015, T. Gosliner GoogleMaps . CASIZ 208190 , one specimen, tissue removed for molecular study, Manila Channel , 13.5223°N, 120.9485°E, Puerto Galera, Mindoro Oriental, Philippines, 13 April 2015, T. Gosliner GoogleMaps . CASIZ 217345 , one specimen, Bethlehem 1 3.6 7 3 2 9°N, 1 2 0.8 4 0 9 3°E, T i n g l o y, B a t a n g a s, Philippines, 18 April 2016, T. Gosliner . CASIZ 177617 , one specimen, dissected, Bethlehem 13.67329°N, 120.84093°E, Tingloy, Batangas, Philippines, 17 April 2008, T.Gosliner GoogleMaps . CASIZ 208652 , one specimen, Boulders , 13.51286°N, 120.98309°E, Puerto Galera, Mindoro Oriental, Philippines, 26 April 2015, T. M. Gosliner GoogleMaps . CASIZ 208646 , one specimen, La Laguna, 13.52496°N, 120.97114°E, Puerto Galera, Mindoro Oriental, Philippines, 8 April 2015, T. M. Gosliner GoogleMaps . CASIZ 0 69756, north end of Pig (Tab) Island, Madang, Papua New Guinea, 10 m depth, 30 July 1989, T. Gosliner . CASIZ 0 68776, one specimen, Cement Mixer Reef , Madang, Papua New Guinea, 16 July 1989, T. Gosliner . CASIZ 0 75842, one specimen, Barracuda Point , Madang, Papua New Guinea, 7 m depth, 23 November 1990, T. Gosliner .

Geographical distribution

Known from the western Indian Ocean of Aldabra Atoll to the western Pacific of Vanuatu, Indonesia, Papua New Guinea, the Philippines and Japan ( Gosliner et al., 2008).

Etymology

This species is named Hypselodoris lacuna based on the translucent areas on the notum that resemble holes in the body wall.

Description

External morphology: Living animals ( Fig. 18 View Figure 18 A–D) small, reaching 12 mm in length. Body opaque white, with round translucent areas on notum that resemble holes in body wall. Two large, translucent circles situated posterior to rhinophores, and smaller circles located over surface of notum. Small black spot located in the centre of most smaller translucent circles. Ring of blue spots present along submarginal area of notum. Centre of spot darker than outer diffuse area. Blue spots also present on posterior end of foot. Gill branches white, with reddish tip. Seven unipinnate gill branches present in all specimens examined. Perfoliate rhinophores white basally and bright red apically, bearing about eight or nine densely arranged lamellae.

Mantle glands: Subcutaneous mantle glands simple, rounded in shape ( Fig. 2J View Figure 2 ). Six to twelve glands present posteriorly in seven specimens examined. Anterior and lateral glands absent.

Buccal armature: Muscular portion of buccal mass much smaller than oral tube. Buccal mass consisting of chitinous labial cuticle at anterior end of muscular portion of buccal mass. Jaws bearing numerous rodlets, narrow and acutely pointed, largely undivided but with an occasional bifid cusp ( Fig. 19A View Figure 19 ). Radular formula of paratype (CASIZ 208587) 46 × 36.0.36. Rachidian row of teeth absent ( Fig. 19B View Figure 19 ). Innermost lateral teeth with one or two small, triangular denticles on inner side of bifid primary cusps and one outer denticle. Inner cusp of bifid cusp much longer than outer one. Next several laterals lacking inner and outer denticles on sides of primary bifid cusps. Midlateral teeth ( Fig. 19C View Figure 19 ) also lacking inner denticles, but with a single triangular outer denticle or entirely lacking denticles. Outer cusp of bifid cusp much shorter than inner one. Outer teeth lacking inner denticles, with up to four triangular outer denticles ( Fig. 19D View Figure 19 ). Outermost teeth with narrower base and more elongate tooth shape.

Reproductive system: Reproductive organs fully mature ( Fig. 13D View Figure 13 ). Ampulla thick, tubular and slightly curved, narrowing somewhat before bifurcating into the oviduct and vas deferens. Short oviduct entering female gland mass near albumen gland. Prostatic proximal portion of vas deferens curved and thick, narrowing gradually while transitioning into narrow, muscular ejaculatory portion. Ejaculatory portion curving into segment entering short, wider penial bulb. Penial bulb adjacent to curved, narrow vaginal duct at common gonopore. Distal end of vas deferens devoid of penial hooks. Female gland mass consisting of large mucous gland and small membrane and albumen glands. Large, lobate vestibular gland situated near exit of mucous gland. Elongate, curved vagina leading to minute receptaculum seminis and larger spherical, thin-walled receptaculum seminis. Relatively short uterine duct emerging from vagina distal to junction of receptaculum and bursa.

Remarks

Hypselodoris lacuna is unique among members of this genus in having translucent circles and a ring of small blue spots along the submarginal area of the notum. Its colour pattern more closely resembles that of Chromodoris aspersa ( Gould, 1852), but it has red rhinophoral and gill pigment rather than light orange. This species is at the base of a clade that includes H. iba , H. reidi , H. regina , H. jacksoni , H. cerisae and H. krakatoa , although that relationship is weakly supported. All members of this clade, with the exception of H. lacuna , have an elevated gill pocket and mantle glands arranged all around the perimeter of the mantle margin ( Gosliner & Johnson, 1999; Wilson & Willan, 2007; present study). Hypselodoris lacuna has only posterior mantle glands, and the gill pocket is not elevated. One feature that H. lacuna shares with other members of this clade is the presence of radular teeth where the inner cusp is much longer than the outer one.