Hypselodoris ghardaqana

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: 24-26

publication ID

http://doi.org/ 10.1093/zoolinnean/zly048

publication LSID


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scientific name

Hypselodoris ghardaqana



( FIGS 1E, 2E, 12, 13A)

Chromodoris ghardaqana Gohar & Aboul-Ela, 1957: 220  –222, pl. 1, fig. 3, pl. 2, figs. 4, 5; Risbecia ghardaqana Gohar & Aboul-Ela, 1957  ; Rudman, 1987: 374, figs 37b, 39b, 40–41.

Material examined

CASIZ 192282, two specimens, one dissected, West Manghar Island , 16.9504333 N °, 041.8108667E °, Red Sea, Saudi Arabia, 8 March 2013, T. GoslinerGoogleMaps  .

Geographical distribution

Known only from the Red Sea ( Rudman, 1987; present study).


External morphology: Living animals ( Fig. 1EView Figure 1) large, reaching 75 mm in length. Body translucent white, with irregular large yellowish spots and a continuous dark blue marginal band. Translucent white foot ornamented by dark blue marginal band. Gill white,

with dark blue line on interior and outer edge or gill

rachis. Thirteen unipinnate gill branches. Perfoliate rhinophores white basally and dark blue apically, bearing ~18 densely arranged lamellae.

Mantle glands: Subcutaneous mantle glands simple rounded in shape ( Fig. 2EView Figure 2). Glands dense, found along entire mantle margin except at anterior end.

Buccal armature: Muscular portion of buccal mass approximately equal in length to oral tube. Buccal mass consisting of chitinous labial cuticle at anterior end of muscular portion of buccal mass. Jaws bearing numerous rodlets ( Fig. 12AView Figure 12). Rodlets narrowly triangular, with single, acutely pointed apex. Radular formula of holotype 63 × 55.0.55. Rachidian row of teeth absent ( Fig. 12BView Figure 12). Innermost lateral teeth have a single small triangular denticle on inner side of bifid primary cusp and lacking outer denticles. Next several laterals lacking inner triangular denticle and also lacking denticles on outer side of primary bifid cusps. Outer lateral cusp much shorter than inner one. Midlateral teeth ( Fig. 12CView Figure 12) also lacking inner denticles but possessing five to ten triangular outer denticles. Outer cusp of bifid cusp much shorter than inner one. Outer teeth lacking inner denticles and having six to eight triangular outer denticles ( Fig. 12DView Figure 12). Outermost teeth with narrower base and more elongate tooth shape.

Reproductive system: Reproductive organs fully mature ( Fig. 13AView 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 slightly while transitioning into muscular, ejaculatory portion. Ejaculatory portion curving into segment entering elongate, slightly widened penial bulb. Penial bulb adjacent to curved, 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. Elongate, curved vagina leading to minute receptaculum seminis and larger spherical, thin-walled receptaculum seminis. Relatively short uterine duct emerging from about half of the length along duct to bursa.


This species was originally described as a species of Chromodoris  distinct from both C. pulchella (Rüppell & Leuckart, 1828)  and Chromodoris annulata Eliot, 1904  ( Gohar & Abu-Ela, 1957). Rudman (1987) maintained the distinctness of the three species but transferred C. pulchella  and C. ghardaqana  to Risbecia  . Johnson & Gosliner (2012), based on molecular phylogeny, showed that species of Risbecia  are nested in Hypselodoris  and that maintenance of Risbecia  creates a paraphyletic Hypselodoris  . They also demonstrated that C. annulata  should be considered as a species of Goniobranchus  . Hypselodoris ghardaqana  was not included in their analysis but was hypothesized to be a member of the Risbecia  clade of Hypselodoris  . A surprising result of the present study is that H. ghardaqana  is not a close relative of the members of the Risbecia  clade, but rather is sister to H. bollandi  . Hypselodoris  nigrolineata is sister to both H. ghardaqana  and H. bollandi  . The colour pattern of H. bollandi  is similar to that of H. ghardaqana  in that both species have a white body colour with yellow spots. The rhinophores and gill of H. ghardaqana  are ornamented with dark blue pigment, whereas they are ornamented with red in H. bollandi  . Hypselodoris bollandi  also has dark brown pigment on the notum. In all three species, the middle lateral teeth bifid cusps have a characteristic shape, with an elongated inner cusp and a short outer cusp, with numerous denticles below the outer cusp. The colour pattern of H. ghardaqana  is remarkably convergent with that of its sympatric congener, H. pulchella  .














Hypselodoris ghardaqana

Epstein, Hannah E., Hallas, Joshua M., Johnson, Rebecca Fay, Lopez, Alessandra & Gosliner, Terrence M. 2018

Chromodoris ghardaqana

Gohar & Aboul-Ela 1957: 220

Risbecia ghardaqana

Gohar & Aboul-Ela 1957