Hypselodoris yarae, 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 : 53-56

HYPSELODORIS YARAE GOSLINER & JOHNSON SP. NOV.

( FIGS 32 –34)

LSID: urn:lsid:zoobank.org:act:5F96599D-CBC6-4073-BF7C-6A059710F8B8

Hypselodoris maculosa not H. maculosa ( Pease, 1871) : misidentification in part, Gosliner & Johnson, 1999: specimen CASIZ 073533; Fraser, 1999; Poddubetskaia, 2003; Lederman, 2005; Houben, 2007.

Hypselodoris sp. 1 Gosliner et al., 2008: 259, middle photograph.

Hypselodoris cf. maculosa Johnson & Gosliner, 2012 .

Hypselodoris sp. 4 Gosliner et al., 2015: 255, upper left photograph.

Hypselodoris sp. 1 Gosliner et al., 2015: 253, upper right photograph

Type material

Holotype: CASIZ 223316 , one specimen, 17 mm, subsampled for molecular study, Doodles dive site (26.8389°S 328917°E), Ponta do Ouro, Mozambique, 16 m depth, 11 May 2014, Yara Tibiriçá.

Paratypes: CASIZ 0 73533, one specimen, Ifaty, SW Madagascar, 1 km west of Mora Mora Resort , 2 m depth, 27 March 1990, T. Gosliner . CASIZ 223317 , one specimen, 26 mm, dissected, subsampled for molecular study, in front of Kwalala Lodge , (14°29 ′ 25 ″ S, 40°44 ′ 30 ″ E), Nacala, Mozambique, 12 m depth, 9 June 2014, Yara Tibiriçá .

Geographical distribution

Known only from Madagascar and Mozambique and possibly from Kenya ( Gosliner et al., 2015: 252, upper right photograph), South Africa ( Fraser, 1999), Sri Lanka ( Houben, 2007) and the Red Sea ( Poddubetskaia, 2003; Lederman, 2005).

Etymology

The name yarae honors Yara Tibiriçá, who has advanced our knowledge of western Indian Ocean nudibranchs and collected several specimens of this species.

Description

External morphology: Living animals ( Fig. 32 ) of moderate size, 20–35 mm in length. Entire dorsal surface light pink to tan, with thick orange band encircling the margin of notum. Marginal band often with undulating margins on inner side. Notum with series of narrow, opaque white longitudinal lines. Large plum to brown spots located between lines. Sides of body and margin of foot same colour as notum. Gill branches orange basally, with opaque white apices. Seven to nine unipinnate, well-elevated gill branches present on notum. Bulb of rhinophores opaque white, with two prominent orange bands and traces of third band basally. Base of rhinophores translucent white. Bulb with ~12–13 densely packed lamellae.

Mantle glands: Mantle glands present along entire mantle margin, larger posteriorly and anteriorly ( Fig. 33A ).

Buccal armature: Muscular portion of buccal mass smaller in size than oral tube. Chitinous labial cuticle elongate ( Fig. 34A ), narrow, found at anterior end of muscular portion of the buccal mass bearing numerous jaw rodlets ( Fig. 34B ). Rodlets straight, narrow and long, with long base. Rodlets evenly curved, with single, acutely pointed apex with lateral lobes. Radular formula of paratype (CASIZ 073533) 45 × 31.0.31 ( Fig. 34C ). Rachidian row of teeth absent ( Fig. 34D ). Innermost lateral teeth having zero to two short denticles on inner side of bifid primary cusp and one or two denticles on the outer side of the bifid cusp. Outer cusp of bifid cusps about same size as inner one. Second lateral tooth and next several laterals lacking inner denticles, possessing primary bifid cusps and one ot three outer denticles. Midlateral teeth ( Fig. 34E ) all lacking inner denticles but with three or four prominent outer denticles. Outermost teeth ( Fig. 34F ) having a narrower base and three outer denticles.

Reproductive system: Reproductive organs of the paratype (CASIZ 223317) are fully mature ( Fig. 33B ). Ampulla think, tubular and curved, narrowing somewhat before bifurcating into oviduct and vas deferens. Short oviduct entering female gland mass near albumen gland. Prostatic proximal portion of vas deferens long, convoluted, curved and thick and narrowing abruptly as it transitions into muscular ejaculatory portion. Ejaculatory portion moderately short, straight, narrow, entering moderately short, wider penial bulb. Penial bulb adjacent to straight, moderately wide 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. Relatively long vagina leading to small, curved receptaculum seminis and larger spherical, thin-walled bursa copulatrix. Receptaculum seminis located in distal half of vaginal length. Long uterine duct, wide at base of vagina, narrowing and entering female gland mass near the albumen gland.

Remarks

This species was initially recognized as genetically distinct from H. maculosa by Johnson & Gosliner (2012), as Hypselodori s sp. cf. maculosa . The present study also indicates a basal position as being sister to the remaining members of its large clade. Its distinctness is also strongly supported by the ABGD analysis. Externally, there are differences between H. yarae and other members of the H. maculosa clade. This species has a darker body colour than H. alburtuqali , H. decorata and H. maculosa , with fewer, larger brown to plum spots. It also differs from H. alburtuqali in having a wide orange margin that usually has undulations along its inner margin. The jaws of H. yarae are much narrower and more elongate than are those of H. alburtuqali ( Fig. 3A ), H. decorata ( Fig. 10A ) and H. maculosa ( Fig. 11A ). The most distinctive anatomical features of H. yarae from the above three species are the basal insertion of the uterine duct into the vagina that has an expanded base, and the more basal position of the receptaculum seminis.

Figures

Figure 3. Hypselodoris alburtuqali Gosliner & Johnson sp. nov., CASIZ 192295, holotype, buccal armature. A, portion of jaw. B, jaw rodlets. C, entire radula. D, innermost teeth. E, middle lateral teeth. F, outermost teeth.

Figure 10. Hypselodoris decorata (Risbec, 1928). A, entire jaw, CASIZ 190661. B, jaw rodlets, CASIZ 191214. C, entire radula, CASIZ 190661. D, inner lateral teeth, CASIZ 190661. E, middle lateral teeth, CASIZ 190661. F, outer lateral teeth, CASIZ 190661.

Figure 11. Hypselodoris maculosa (Pease, 1871), CASIZ 139545. A, entire jaw. B, jaw rodlets. C, entire radula. D, inner lateral teeth. E, middle lateral teeth. F, outer lateral teeth.

Figure 32. Hypselodoris yarae Gosliner & Johnson sp. nov., living animals. A, photograph of specimen from Îles de Radama, October 2005. B, holotype, CASIZ 223316, Ponto de Ouro, Mozambique, photograph by Yara Tibiriçá. C, paratype, CASIZ 223317, Nacala, Mozambique, photograph by Yara Tibiriçá. D, paratype, CASIZ 073533, Ifaty, Madagascar.

Figure 33. Hypselodoris yarae Gosliner & Johnson sp. nov. A, mantle glands. B, reproductive system, scale bar: 0.5 mm. am, ampulla; bc, bursa copulatrix; ej, ejaculatory portion of the vas deferens; fgm, female gland mass; p, penis; pr, prostatic portion of vas deferens; rs, receptaculum seminis; ud, uterine duct; v, vagina; vg, vestibular gland.

Figure 34. Hypselodoris yarae Gosliner & Johnson sp. nov., buccal armature, holotype, CASIZ 223316. A, entire jaw. B, jaw rodlets. C, entire radula. D, inner lateral teeth. E, middle lateral teeth. F, outer lateral teeth.