Hypselodoris brycei Epstein & Hallas & Johnson & Lopez & Gosliner 2018
Creators: name: Epstein, Hannah E.
name: Hallas, Joshua M.
name: Johnson, Rebecca Fay
name: Lopez, Alessandra
name: Gosliner, Terrence M.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Nudibranchia
Chromodorididae
Hypselodoris
Hypselodoris brycei

description: HYPSELODORIS BRYCEI
GOSLINER & JOHNSONSP. NOV.
(FIGS 1B, 4C, 5)
LSID: urn:lsid:zoobank.org:act: CBB7E0BA-43CF- 47E7-9371-5FD79772D571
C h r o m o d o r i s b u l l o c k i m i s i d e n t i f i c a t i o n, n o t C. bullockii Collingwood, 1881, Wells & Bryce, 1993: 8, upper figure.
H y p s e l o d o r i s b u l l o c k i m i s i d e n t i f i c a t i o n, n o t H. bullockii (Collingwood, 1881), Debelius, 1997: 233 uppermost photograph.
Hypselodoris cf. bullocki 2 Debelius & Kuiter, 2007: 117, upper photographs.
Hypselodoris sp. 9 Gosliner et al., 2008: 268, bottom photograph.
Hypselodoris sp. 18 Gosliner et al., 2015: 263, upper left photograph.
Type material
Holotype: WAM S96082, subsampled for molecular study, Epsilon Island, Montebello Islands, Western Australia, 20.4513°S, 115.5827°E, 7 m depth, 15 April 2015, S. Morrison.
Paratypes: WAM S96083, subsampled for molecular study, Western Australia, 20.4513°S, 115.5827°E, 7 m depth, 15 April 2015, A. Hara and A. Hosie. WAM S96157, subsampled for molecular study, 5.2 km NE of Ah Chong Island, Montebello Islands, Western Australia, 20.4992°S, 115.5899°E, 15 m depth, 16 April 2015, A. Hara. WAM 12628, five specimens, one dissected, St. 16, Dampier Archipelago, NW Legendre Island, Western Australia, 31 July 2000, C. Bryce.
Type locality
Epsilon Island, Montebello Islands.
Geographical distribution
Known only from the Houtman Abrolhos Islands to the Exmouth Region and Dampier Archipelago, Western Australia (Wells & Bryce, 1993; Debelius, 1997).
Etymology
Hypselodoris brycei is named for our colleague, Clay Bryce of the Western Australian Museum, who has collected and photographed very many new species of nudibranchs. He was the first to document this new species and has collected most of the material studied here.
Description
Externalmorphology: Livinganimals(Fig.1B)moderately large, reaching 50 mm in length. Body translucent white, with a deep violet marginal band encircling the margin of notum. More purple submarginal pigment found inside marginal band. Nine to 11 thin, unipinnate gill branches on notum. Gill branches with purple base and red–orange outer two-thirds. Base of gill pocket purple. Bulb and base of rhinophores bright red orange, with ~41 small lamellae. Base of rhinophore sheath deep violet to purple. Edge of foot with purple marginal band.
Mantle glands: Subcutaneous mantle glands entirely absent.
Buccal armature: Muscular portion of buccal mass about twice length of oral tube. Chitinous labial cuticle found at anterior end of muscular portion of the buccal mass bearing numerous jaw rodlets (Fig. 5A). Rodlets narrow, with short base and evenly curved, with single, acutely pointed apex. Radular formula of one paratype, WAM 12628, ~70 × 92.0.92. Rachidian row of teeth absent (Fig. 5B). Innermost lateral teeth having one rounded denticle on inner side of bifid primary cusp with another three to four outer denticles. Denticles not extending far beyond middle of elongate primary cusp. Next several laterals lacking inner triangular denticle but possessing four to six denticles on outer side of primary bifid cusps. Midlateral teeth (Fig. 5C) all lacking inner denticles, but having five to nine rounded, triangular outer denticles and extended primary cusp. Outermost teeth having a narrower base and shorter tooth shape, with five or six rounded outer denticles (Fig. 5D), often larger than bifid cusps.
Reproductive system: Reproductive organs of the holotype fully mature (Fig.4C). Ampulla thick, tubular and slightly 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 convoluted, curved and thick and narrowing slightly as it transitions into muscular ejaculatory portion. Prostatic portion enveloping bursa copulatrix. Ejaculatory portion convoluted, narrow, entering short, wider penial bulb. Penial bulb adjacent to slightly curved, 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, straight receptaculum seminis and larger spherical, thin-walled receptaculum seminis. Receptaculum seminis appressed against vagina. Moderately long uterine duct emerging from vagina close to base of bursa and female gland mass, near the albumen gland.
Remarks
The colour pattern of H. brycei is distinctive from all other members of the genus. It most closely resembles Thorunna daniellae (Kay & Young, 1969) (Gosliner et al., 2015: 250 upper right photograph), but H. brycei is a larger species, reaching 50 mm in length, whereas T. daniellae rarely exceeds 20 mm in length. Our molecular phylogeny (Fig. 35) clearly indicates that H. brycei is in the H. bullockii clade, where it is the sister species to H. apolegma (Yonow, 2001). Yonow (2001) described H. apolegma as a species of Risbecia, but Johnson & Gosliner (2012) clearly demonstrated that Risbecia is nested within Hypselodoris and that H. apolegma is not in the same clade as the species formerly included in Risbecia but is closely related to H. bullockii. Of the members of the H. bullockii clade, H. brycei is the only species with a white body colour and a violet marginal band. All members of the H. bullockii clade lack mantle glands and are unique among Hypselodoris species in this regard. The radula of H. apolegma appears to contain more teeth than that of H. brycei (Yonow, 2001; present study). Yonow (2001) described the radula formula of H. apolegma as 96 × 120.0.120, whereas the specimen of H. brycei had a formula of 70 × 92.0.92. The denticles of the radular teeth of H. brycei do not extend much beyond the middle of the primary cusp, whereas in H. apolegma they extend almost to the end of the cusp. The reproductive system of H. brycei has a much shorter penial papilla and long ejaculatory duct, whereas H. apolegma (Fig. 4D) has a longer, wider penial bulb and a shorter ejaculatory duct.
description: Published as part of 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), pp. 1-74 in Zoological Journal of the Linnean Society 20 (1) on pages 12-14, DOI: 10.1093/zoolinnean/zly048, http://zenodo.org/record/2632578