Chromodoris baqe Bonomo & Gosliner 2020, sp. nov.
Creators: name: Bonomo, Lynn J.
name: Gosliner, Terrence M.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Nudibranchia
Chromodorididae
Chromodoris
Chromodoris baqe

description: Chromodoris baqe Bonomo & Gosliner sp. nov.
Figures (2B, 5, 6)
urn:lsid:zoobank.org:act: E0B9C945-09D3-40C1-9445-C8512B7F1ED6
Chromodoris aspersa — Rudman 1983: 145, Figures 12D, 18C, 19 B, D, & F, misidentification, not C. aspersa (Gould, 1852); Yonow, 2008: 180, four photos, misidentification.
Chromodoris sp. 18— Gosliner et al. 2018: 141, middle right photograph.
Chromodoris sp. 6— Gosliner et al. 2015: 213, top right photograph.
Type material. Holotype: CASIZ 192285, one specimen, subsampled. Marka Island 18.22667° N 41.31733° E, Red Sea, Saudi Arabia, 6 March 2013, Arthur Anker.
Paratype: CASIZ 192279, two specimens, one specimen subsampled. Zahrat Durakah, Red Sea, Saudi Arabia, 11 March 2013, T.M. Gosliner. CASIZ 192287, four specimens, one specimen (A) subsampled and dissected. Abulad Islands, 16.79767° N 41.199° E, Red Sea, Saudi Arabia, 7 m depth, 10 March 2013, T.M. Gosliner.
Type locality. Marka Island, Red Sea, Saudi Arabia.
External morphology. Living animals (Fig. 2B) are relatively large, with a maximum length of 25 mm. The body is cream-white with different sized spots that cover the entire mantle and foot. The larger spots are dark purple and diffuse outwards, while the smaller spots are solid dark purple in color. The marginal band is orange and surrounds the entire mantle and visible portion of the foot. Eight to ten unipinnate gill branches are a solid yellowish-cream to orange in color. The perfoliate rhinophores are orange with 20 distinct lamellae. The posterior end of the foot extends well past the posterior end of the mantle and is ornamented the same as the mantle. On either side of the mouth is a pair of digitiform oral tentacles.
Internal morphology. Mantle glands: The mantle glands are subcutaneous, but hard to see in the preserved specimen. The mantle glands are located around the entire mantle, except for the anterior portion of the specimen. These mantle glands are visible in photographs (Fig. 2B) and are in single lined offshoots from the main connections. The shorter glands are small rounded bifurcated blobs that look similar to a heart in shape (Fig. 5A).
Buccal mass and radula: The muscular portion of the buccal mass is slightly larger than the oral tube length. A chitinous labial cuticle is found at the anterior end of the muscular portion (Fig. 5B) with bifurcated jaw elements (Figs. 6 A–B). The radular formula in two paratypes, CASIZ 192279A and CASIZ 192287A, is 59 x 39.1.39 and 63 x 46.1.46, respectively (Fig. 6C). The rachidian tooth is thin and linear without a distinct cusp. On either side of the rachidian, the inner lateral teeth have 2–3 denticles on the inner side and 2–3 on the outer side (Fig. 6D). The inner lateral tooth (Fig. 6D) has an elongate central cusp that is twice the length of the adjacent denticles. The remaining laterals only have denticles on the outer side of the central cusp. The middle lateral teeth have an elongate cutting edge with 5 to 7 pointed denticles (Fig. 6E). The outer lateral teeth are rounded and elongate with 3 to 6 denticles depending on the amount of wear that has occurred on the teeth (Fig. 6F).
Reproductive system (Fig. 5C): The thin pre-ampullary duct connects the ovotestis with the elongate ampulla. The ampulla narrows proximally and divides into a short oviduct and an elongate vas deferens. The distal portion of the vas deferens is wide, convoluted, and prostatic. The prostatic portion narrows proximally and enters the short curved ejaculatory segment. This segment expands into the very long bulbous penial bulb, which also joins with the distal end of the vagina. The vagina is moderately long and straight and enters the base of the thin-walled, spherical bursa copulatrix. Just below the base of the bursa is the receptaculum seminis duct, which connects with the pyriform curved receptaculum seminis. Along the length of the receptaculum seminis duct is a short branch of the uterine duct that enters the female gland mass. The female gland mass is composed of a small albumen and membrane glands and a larger mucous gland. A small bulbous vestibular gland is present near the opening of the genital atrium.
Etymology. This species is named Chromodoris baqe after the Arabic word for spots, since the entire nudibranch is covered in black spots and looks similar to a cow.
Geographical distribution. This nudibranch is only known from the Red Sea.
Remarks. Doris aspersa Gould, 1852 was originally described from the Hawaiian Islands and has been documented from several localities throughout most of the Indian and Pacific Oceans (Gosliner et al. 2018, as Chromodoris aspersa). Kay and Young (1969) described the anatomy of Hawaiian specimens and Rudman (1983) detailed the anatomy of specimens of Chromodoris aspersa (Gould 1852) and compared the morphology of western Pacific and Red Sea specimens, concluding that the Red Sea specimens were not distinct enough to be considered as a separate species. However, in Rudman (1973) and Gohar & Soliman (1967), the Red Sea species was not considered as distinct from C. aspersa. Rudman did note that Hawaiian specimens differed from those found in the western Pacific in that they lacked the orange marginal band present in the western Pacific and Indian Ocean specimens. Layton et al. (2018) found that all Pacific specimens of C. aspersa represented a single lineage and showed insignificant differentiation between populations found from the Hawaiian Islands, Fiji, Samoa, Australia, Wake Island, Japan, the Philippines and Papua New Guinea. However, they did find significant genetic differences between Red Sea specimens and the remainder of the specimens, which prompted the inclusion of this species in the present paper.
Rudman (1983: 145) listed several synonyms of Chromodoris aspersa. Doris amabilis Kelaart 1859 from Sri Lanka was not illustrated and little can be said about its relationship to C. aspersa. Although it was not illustrated by Kelaart (1859), Eliot (1906: pl. 42, fig. 1) did depict it. Doris amabilis has smaller spots that appear reddish, rather than purple, on its mantle and has no yellow marginal band. Chromodoris inornata (Pease 1871), also known as Glossodoris inornata Pease 1871, from French Polynesia has small purple spots and no large yellow marginal band. Chromodoris pallescens Bergh 1874 (pl. 7, fig. 4), also from French Polynesia, has a white mantle and purple spots with a longer narrower body and an extended posterior foot. This indicates that C. pallescens is indeed C. aspersa as Rudman (1983) suggested and not C. baqe. Doris punctulifera Bergh 1874 (pl. 1, figs. 19 & 20) has a white mantle and purple spots with a narrow orange marginal band. This would indicate that it is actually C. aspersa as Rudman (1983) noted. Rudman (1983) also included several other synonyms for C. aspersa or misidentified specimens in his discussion. Due to these species having distinct morphological differences and biogeographical distributions, they do not represent the same species that was described here as Chromodoris baqe.
The ABGD and bPTP analyses conducted by Layton et al. (2018) and that of the present study, shows that this species represents a distinct, unnamed taxon that is sister to C. aspersa. There is a minimum genetic distance of 11.12% uncorrected pairwise distance between C. baqe and C. aspersa according to the ABGD analysis. These two species are sister to the remaining species of Chromodoris according to a BI posterior probability of 1, but only had a ML bootstrap support of 48%. However, they do form a strong clade together that has strong BI posterior probabilities and ML bootstrap support.
The Red Sea specimens described here as C. baqe have several distinct external characters that clearly distinguish them from C. aspersa. First and foremost, the body of C. baqe is ovoid with a significant overhang of the mantle over the lateral edges of the foot, whereas C. aspersa is long and narrow with the edge of the mantle does not extend much beyond the lateral edge. The general body color of C. baqe is a cream color as compared to the translucent white color of C. aspersa. The dark purple spots of C. baqe are larger, slightly raised, and diffuse, whereas they are smaller with a faint purple ring in C. aspersa that almost make the spots appear out of focus as previously discussed in Rudman (1983). In C. baqe spots are present on the posterior end of the foot, whereas spots are entirely absent on the posterior foot in C. aspersa.
The mantle glands of C. baqe are found along the margins of the mantle from almost the posterior end of the body to just beyond the midpoint (Fig. 5A). In C. aspersa the mantle glands are absent from the posterior end of the animal and are continuous from just behind the gill for about three fourths of the body length, terminating just posteriorly to the rhinophores. The radular characters and tooth shape do not vary significantly between C. aspersa and C. baqe. The reproductive system of C. baqe has a much shorter receptaculum seminis and a broader penial bulb than that described for C. aspersa by Kay and Young (1969, fig. 42A, B).
description: Published as part of Bonomo, Lynn J. & Gosliner, Terrence M., 2020, Adding stars to the Chromodoris (Nudibranchia, Chromodorididae) galaxy with the description of four new species, pp. 401-435 in Zootaxa 4819 (3) on pages 417-420, DOI: 10.11646/zootaxa.4819.3.1, http://zenodo.org/record/4397003