Hypselodoris iba, 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 : 26-29

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.5980678
persistent identifier	https://treatment.plazi.org/id/411BF606-FFFB-FFA1-FCEA-FDE1FB626BA0
treatment provided by	Plazi
scientific name	Hypselodoris iba
status	sp. nov.

Treatment

HYPSELODORIS IBA GOSLINER & JOHNSON View in CoL SP. NOV. (FIGS 2F, 13B, 14, 15)

LSID: urn:lsid:zoobank.org:act:A5DF9265-3D8B-4BB8-B54D-DC66C89C7BFC

H y p s e l o d o r i s b u l l o ck i, m i s i d e n t i f i c a t i o n, n o t Chromodoris bullockii ( Collingwood, 1881) View in CoL ; Humann & DeLoach, 2010: 338, middle right and lower left photographs.

Hypselodoris View in CoL sp. 5 Debelius & Kuiter, 2007: 118.

Hypselodoris View in CoL sp. 10 Gosliner et al., 2008: 269, top photograph.

Hypselodoris View in CoL sp. 14 Gosliner et al., 2015: 261, bottom two photographs.

Type material

Holotype: NMP 0 41279 (formerly CASIZ 177511 ), subsampled for molecular study, Aphol’s Reef , 13.65835°N, 120.90144°E, Tingloy, Maricaban Island, Batangas, Philippines, 35 m depth, 21 March 2008, P. Paleracio. GoogleMaps

Paratypes: CASIZ 177777 , dissected, subsampled for molecular study, Aphol’s Reef , 13.65835°N, 120.90144°E, Tingloy, Maricaban Island, Batangas, Philippines, 35 m depth, 23 April 2008, P. Paleracio GoogleMaps . CASIZ 180419 , dissected, subsampled for molecular study, Aphol’s Reef , 13.65835°N, 120.90144°E, Tingloy, Maricaban Island, Batangas, Philippines, 35 m depth, 17 May 2009, P. Paleracio GoogleMaps . CASIZ 186103 , two specimens, Malajibomanoc (Chicken Feather) Island, 13.62772°N, 120.96592°E, Tingloy, Batangas, Philippines, 40 m depth, 16 May 2011, P. Paleracio GoogleMaps .

CASIZ 208587 , scale bar: 0.5 mm. E, Hypselodoris melanesica Gosliner & Johnson sp. nov ., CASIZ 0 69787, scale bar: 0.7 mm. F, Hypselodoris bullockii ( Collingwood, 1881) , CASIZ 0 85905, scale bar: 1.0 mm. G, Hypselodoris paradisa Gosliner & Johnson sp. nov., holotype , CASIZ 191464 , scale bar: 0.5 mm. H, Hypselodoris perii Gosliner & Johnson sp. nov., holotype , NMP 0 41281, scale bar: 0.3 mm. I, Hypselodoris roo Gosliner & Johnson sp. nov., holotype , NMP 0 41282, scale bar: 1.0 mm. J, Hypselodoris rositoi Gosliner & Johnson sp. nov., holotype , NMP 0 41283, scale bar: 1.2 mm. K, Hypselodoris skyleri Gosliner & Johnson sp. nov., CASIZ 177305 , 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 .

CASIZ 217217 , MAB 325, Dead Palm dive site, 13.69493372°N, 120.884687°E, Calumpan Peninsula , Mabini, Batangas, Luzon, Philippines, 30 m depth, 16 April 2016, P. Paleracio GoogleMaps .

Type locality

Aphol’s Reef, Tingloy, Maricaban Island, Batangas, Philippines.

Geographical distribution

Known from Indonesia and the Philippines ( Gosliner et al., 2008).

Etymology: Hypselodoris iba is named for the Tagalog word iba , meaning different or distinctive.

Description

External morphology: Living animals ( Fig. 14 View Figure 14 ) large, reaching 70 mm in length.Body wide, tapering to narrow, rounded posterior end of notum. Foot wide, elongate posteriorly. Gill with six to eight unipinnate branches. Gill branches with white pigment at base, becoming orange in outer portion. Gill pocket well elevated from notum. Rhinophores with 20–24 lamellae. Colour pattern occurs in two distinct morphs. In first morph, body generally uniformly purple, with uniformly wide opaque white marginal band or occasionally orange band. Rhinophores uniformly orange, with orange or purple pigment on base of rhinophore sheaths. Second morph generally off-white to beige, with thin white marginal band, transitioning to orange anteriorly and posteriorly. Submarginal blood red band may be present, transitioning to purple anteriorly. Blood red blotches present on central region of notum, on base of gill pocket and base of rhinophore sheaths. purple band present near opening of rhinophore sheaths. Blood red blotches may also be present on lateral faces of body. Wide purple band present along lateral margin of foot.

Mantle glands: Subcutaneous mantle glands large and concentrated posteriorly, with 12–16 glands. Smaller, irregularly distributed glands present along lateral and anterior margins ( Fig. 2F View Figure 2 ).

Buccal armature: Muscular portion of buccal mass about the same size as the length of oral tube. Chitinous labial cuticle found at anterior end of muscular portion of the buccal mass bearing numerous jaw rodlets ( Fig. 15A View Figure 15 ). Rodlets narrow, triangular with short base and evenly curved, with single, acutely pointed apex. Radular formula of two paratypes 63 × 98.0.98 (CASIZ 177777) and 66 × 88.0.88 (CASIZ 180419). Rachidian row of teeth absent ( Fig. 15B, C View Figure 15 ). Innermost lateral teeth lacking inner denticles or having single acutely pointed denticle on inner side of bifid primary cusp. Outer surface of inner lateral without outer lateral denticles. Next several laterals ( Fig. 15D, E View Figure 15 ) and all but outermost lateral teeth with only a bifid primary cusp. Outer cusp much shorter than inner cusp. Outermost teeth having a narrower base and shorter tooth shape, with zero to two rounded outer denticles ( Fig. 15F View Figure 15 ) below bifid cusps.

Reproductive system: Reproductive organs ( Fig.13B View Figure 13 ) of two paratypes fully mature (CASIZ 177777 and CASIZ 180419). 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 curved and thick and narrowing slightly as it transitions into muscular, ejaculatory portion. Prostatic portion enveloping bursa copulatrix. Ejaculatory portion moderately to highly 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, wide vagina leading to small, curved receptaculum seminis and larger spherical, thin-walled receptaculum seminis. Receptaculum seminis appressed against vagina immediately below bursa copulatrix. Moderately long uterine duct emerging from vagina close to base of bursa and female gland mass, near the albumen gland.

Remarks

This species has been considered as a synonym of H. bullockii ( Humann & DeLoach, 2010) or as an undescribed species ( Debelius & Kuiter, 2007; Gosliner et al., 2008, 2015). This has been complicated further by the fact that H. iba has two distinct colour morphs, and one of them is also similar to H. variobranchia sp. nov. described here. For a detailed comparison, see the remarks on H. variobranchia sp. nov. The most reliable way to distinguish H. iba from members of the H. bullockii clade is by the presence of mantle glands in H. iba . No members of the H. bullockii clade have mantle glands (present study). The two colour morphs have been observed copulating with each other ( Fig. 14C View Figure 14 ; Köhler, 2002). Not only are the two colour morphs observed copulating, but they show very little genetic divergence. The holotype (CASIZ 177511), a light morph specimen, is only 0.3% different in its COI gene from a purple morph specimen from the same locality (CASIZ 180419), and a third specimen (CASIZ 177777, also a light morph) from the same locality is 0.6% different from the other two. The subsequent ABGD analysis confirms that these three specimens are conspecific with each other and distinct from all other species.

Hypselodoris iba is also similar in appearance to Thorunna punicea ( Rudman, 1995). In T. punicea, the gills vibrate when the animal is active, the reproductive system has a large receptaculum seminis and the foot has an opaque white line along its margin. In H. iba , the gills do not vibrate and the foot is lined with purple, and it has a small receptaculum seminis and denticulate outer lateral teeth rather than simply bifid ones. In our phylogenetic analysis, T. punicea clearly nests with other species of Thorunna rather than with members of Hypselodoris .

Hypselodoris iba is a member of large clade that includes H. reidi , H. jacksoni , H. cerisae , H. krakatoa , H. regina and H. lacuna . None of these species has a colour pattern similar to either colour morph of H. iba . 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). Members of this clade also have an inner lateral tooth with a single inner denticle and no denticles on the outer side of the bifid cusps. All members of this clade have the majority of teeth with no inner or outer denticles and the outer cusp of the tooth much smaller than the inner cusp.