Glossodoris acosti Matsuda and Gosliner, 2018

Matsuda, Shayle B. & Gosliner, Terrence M., 2018, Glossing over cryptic species: Descriptions of four new species of Glossodoris and three new species of Doriprismatica (Nudibranchia: Chromodorididae), Zootaxa 4444 (5), pp. 501-529 : 513-515

publication ID	https://doi.org/ 10.11646/zootaxa.4444.5.1
publication LSID	lsid:zoobank.org:pub:6A536780-96AE-42B0-913E-C05767BC63EC
DOI	https://doi.org/10.5281/zenodo.5981634
persistent identifier	https://treatment.plazi.org/id/D5A04090-4080-49EA-962A-43585B65F86D
taxon LSID	lsid:zoobank.org:act:D5A04090-4080-49EA-962A-43585B65F86D
treatment provided by	Plazi
scientific name	Glossodoris acosti Matsuda and Gosliner
status	sp. nov.

Treatment

Glossodoris acosti Matsuda and Gosliner View in CoL , sp. nov.

Figures (2E, 6C, D, 8E, F, 9A–E)

Glossodoris cincta ( Bergh, 1888) View in CoL , ( Rudman 1986 in part, misidentification: 155, figs, 30C, 33B, 35).

Glossodoris View in CoL sp. D Matsuda & Gosliner 2017.

Type Material. Holotype: CASIZ-191352, one specimen, dissected, 18 mm preserved, Papua New Guinea, Madang Province, Rempi, coll: D. Uyeno, 20 November 2012, Papua New Guinea Biodiversity Expedition 2012, orig. fixative 95% EtOH. Tissue sample was removed from the foot for DNA sequencing in Matsuda & Gosliner (2017), GenBank : KT600698 View Materials ( COI) .

Paratypes: CASIZ- 191109, one specimen, 6 mm preserved, Papua New Guinea, Madang Province, coll: Expedition by vacuum, 10 Nov 2012, Papua New Guinea Biodiversity Expedition 2012, orig. fixative 98% EtOH. Tissue sample was removed from the foot for DNA sequencing in Matsuda & Gosliner (2017). CASIZ-158809, one specimen, dissected, 31 mm preserved, Philippines, Luzon, Batangas Province, Mabini (Calumpan Peninsula), Maricaban Strait, Arthur’s Rock, coll: B. Castillo, 7 May 2001, 10 meters, orig. fixative Bouin’s solution. A tissue sample was removed from the foot for DNA sequencing by Johnson & Gosliner (2012) and the extraction was additionally used in Matsuda & Gosliner (2017). CASIZ-175327, one specimen 42mm preserved, Philippines, Bohol Island, Panglao, Sungcolan Bay, fringe mangrove, sand and seagrass, coll: T.M. Gosliner, Y. Camacho, J. Templado, M. Malaquias, M. Poddubetskaia, 9 June 2004, Panglao Expedition 2004, 1–5 meters, orig. fixative Bouin’s solution or 10% formalin.

Etymology. Glossodoris acosti is named after Robert Acosta, a longtime friend and mentor of the first author.

Distribution. Specimens identified in Philippines and Papua New Guinea (present study) and possibly Christmas Island (Indian Ocean) ( Rudman 1986).

External morphology. Glossodoris acosti have an elongate oval mantle that sits high on the well-elevated sides of the body ( Fig. 6C, D View FIGURE 6 ). The mantle edge consists of small permanent and semi-permanent undulations with a larger fold on both sides at the midpoint of the mantle. The coloration of the mantle and foot range from brick red to brown, which is covered with small white spots that are denser closer to the edge of the mantle giving it a textured appearance. Three marginal bands run along the outer edge of the mantle and foot, the outermost light blue, followed by dark green and then a lighter yellow-green ( Fig. 2E View FIGURE 2 ). The color bands on the mantle are more intense than on the foot. The gill forms an arch around the anus that opens posterior, and the gills at both ends of the arc curl inwards. The posterior gill branches form two spirals that are found dorsal to the anterior branches. The gill is large and extends all the way to the mantle margins when fully extended. The lamellae are covered in small white spots with dark colored tips, and while the majority are forked, some are not. In one specimen, the lamellae at the middle of the arc had a notably long fork. The base of the rhinophores are the same color as the mantle that become increasingly whiter approaching the dark tips. The genital pore is located on the right side of the body below the mantle and posterior to the rhinophores.

Internal morphology. Radular structure ( Fig. 9A–E View FIGURE 9 ). The radular ribbon is long and wide ( Fig. 9D View FIGURE 9 ) (radular formula for an 18 mm preserved specimen CASIZ-191352 is approximately 106 x 65.1.65). The rachidian tooth ( Fig. 9A View FIGURE 9 ) is two-thirds of the length of the first lateral tooth and narrows to a dull point. The first lateral tooth has a long central cusp with six well-defined small denticles on each side of the tooth. The inner edges of the first laterals have a thicker ridge behind the denticles. The cusps of the inner laterals are slightly longer and there are approximately 12–15 denticles only on the outer edge. The mid-laterals ( Fig. 9B View FIGURE 9 ) have a more pronounced peen than the inner teeth, and have 8–10 denticles on the outer edge. The outer laterals ( Fig. 9C View FIGURE 9 ) are reduced with a shorter central cusp, a reduced peen, and only small indentations where the denticles are on the inner and midlaterals. The outer three teeth entirely lack any trace of denticles. The jaw rodlets have a unicuspid tip and are slightly curved ( Fig. 9E View FIGURE 9 ).

Reproductive system ( Fig. 8E, F View FIGURE 8 ). The vagina is very long and folded and the bursa copulatrix is of comparable size to the receptaculum seminis sac. The bursa and receptaculum have a common insertion. The penial sac is long and twisted and wraps around the more distal part of the penis. The muscular vas deferens and glandular prostatic portion are also highly convoluted.

Remarks. The color pattern is distinctly different than G. bonwanga and G. andersonae , however closely resembles that of G. sp. cf. cincta . In G. bonwanga , there are only two marginal bands of color (outer black and inner yellow) compared to the three bands of G. acosti (outer light blue, middle dark green and outer yellowish green). Similarly, G. andersonae has a white to light blue outer band, followed by a middle band of dark blue and a yellowish green band that contains numerous opaque white markings. There appear to be subtle, but consistent differences in the external morphology between G. acosti and G. sp. cf. cincta . In G. acosti , the marginal bands are much wider and more subdued than in G. sp. cf. cincta . When fully extended, the gill of G. acosti is much larger (extending to the outer margins of the mantle) and has two distinct spirals found above the lower gill branches ( Fig. 6D View FIGURE 6 ), whereas the gill of G. sp. cf. cincta is smaller and has all branches at one level. Glossodoris acosti closely matches the description of Rudman’s (1986) Philippines-Indonesia color group. This is especially evident in the light blue mantle band noted in Rudman’s Philippines specimen ( Fig. 5 View FIGURE 5 ). It also shares similarities to Rudman’s (1986: figs. 33B, 35) Christmas Island specimen in its reproductive system structure and radular morphology.

The radula in G. acosti and G. sp. cf. cincta are also very similar, however the rachidian tooth in G. acosti ( Fig. 9A View FIGURE 9 ) is less pointed than in G. sp. cf. cincta ( Fig. 9F View FIGURE 9 ) and lacks the bulbous swelling below the apex. The outer laterals in G. acosti have faint indentations where the denticles would be, whereas in G. sp. cf. cincta the outer denticles are completely smooth in the Philippines and Papua New Guinea specimens, although the Madagascar specimen has well-defined denticles all the way to the edge. Further study is needed to determine the range of variation of these radular characters.

The vagina of G. acosti is very long and convoluted, which is similar to G. bonwanga , however it is significantly longer than in G. andersonae and G. sp. cf. cincta . Similarly, the penial papilla of G. acosti ( Fig. 8E, F View FIGURE 8 ) is elongate and twists around the distal portion of the penis, where as it is much shorter and evenly curved in G. sp. cf. cincta ( Fig. 8G, I View FIGURE 8 ).

The ABGD analysis clearly separates G. acosti from other members of the G. cincta clade. The intraspecific pdistances are less than or equal to 2, and interspecific p-distances Ž7 ( Matsuda & Gosliner 2017) ( Fig. 5 View FIGURE 5 ).