Elysia azorica, Martín-Hervás & Carmona & Jensen & Krug & Vitale & Cervera, 2024

Martín-Hervás, M. Rosario, Carmona, Leila, Jensen, Kathe R., Krug, Patrick J., Vitale, Fabio & Cervera, Juan Lucas, 2024, A global phylogeny of Elysia Risso, 1818 (Gastropoda: Heterobranchia): molecular systematic insights focusing on European taxa and description of a new species, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 200 (3), pp. 670-689 : 680-682

publication ID

https://doi.org/ 10.1093/zoolinnean/zlad086

persistent identifier

https://treatment.plazi.org/id/03BF216A-FFDC-FFAD-FC75-F9EEFEF10C9B

treatment provided by

Plazi

scientific name

Elysia azorica
status

sp. nov.

Elysia azorica View in CoL sp.nov.

( Figs 6A View Figure 6 , 7A View Figure 7 )

urn:lsid:zoobank.org:pub:C01F2876-A12F-4B37-8841-3D19D8FC617D .

References:

Elysia flava (non Verrill, 1901): Malaquias et al. (2009).

Material examined:

Holotype: MNCN15.05 View Materials /47823 one specimen, dissected, 6 mm length alive, Praia de Porto Pim , (38°31ʹ27.2ʹʹN, 28°37ʹ32.4ʹʹW), Ilha do Faial, the Azores, August 2007 . Paratypes: MNCN15.05 View Materials /47823A, one specimen, 3.5 mm preserved length, Praia de Porto Pim , (38°31ʹ27.2ʹʹN, 28°37ʹ32.4ʹʹW), Ilha do Faial, the Azores, August 2007 ; MNCN15.05 View Materials /47823B, one specimen, 3 mm preserved length, Praia de Porto Pim , (38°31ʹ27.2ʹʹN 28°37ʹ32.4ʹʹW), Ilha do Faial, the Azores, August 2007. All specimens were collected by Manuel Malaquias in the infralittoral zone at 6 m depth .

External morphology:

Adults with total length about 6 mm (present study). Overall coloration orangish, with opaque white papillae on edges of parapodia ( Fig. 6A View Figure 6 ). Some scattered white dots also present on head and sides of parapodia. Digestive gland visible through skin as a dark-green pigment. Body relatively short and wide. Small eyes located behind the rhinophores. Rhinophores relatively long, rolled and uniform with body colour.

Renopericardial prominence small with bright white spots. Branching of dorsal ‘vessels’ not evident on preserved specimens. Large parapodia extend to posterior end of body, with undulated edges. Foot sole not distinctly demarcated and the posterior end of body blunt-ended.

Internal anatomy:

Pharynx elongated and very small.Oesophagus with a small pouch. Radula with 17 teeth (MNCN15.05/47823), seven in ascending limb and 10 in descending limb. Ascus lost during preparation. Leading tooth wide, with a slightly curving cusp tip, bearing a fine, blunt denticulation on cusp and one smooth lateral edge ( Fig. 7A View Figure 7 ). Housing depression for interlocking teeth extending half total tooth length. Base of tooth approximately half total tooth length.

Reproductive system triaulic ( Fig. 8 View Figure 8 ) with a robust and cone-shaped penis, devoid of stylet, and with a long and thin vas deferens. Female gland complex consisted of different arrangements of glandular tissue, where the mucous gland constituted the largest portion. Hermaphroditic follicles densely distributed throughout parapodia. Rounded ampulla present and a small, spherical genital receptacle under female gland complex.Albumen gland formed by a branched system whose connections were diffuse in some sections.

Etymology:

The species name azorica refers to the collection site from which specimens were found (Ihla do Faial, the Azores) and is a Latin feminine adjective in the nominative case, in gender agreement with the genus.

Type locality: Praia de Porto Pim, Ilha do Faial, the Azores.

Geographical distribution:

Species only known from the eastern Atlantic, Praia de Porto Pim, Ihla do Faial , the Azores (present study).

Remarks:

Elysia azorica sp. nov. is easily recognizable alive by its bright and translucent orange colour, which allows the digestive gland to be observed through the skin, and the presence of opaque white rounded papillae along the edge of the parapodia. Externally this species resembles the Atlantic E. flava and the Pacific species E. obtusa Baba, 1938 , but they mainly differ in the external coloration. Aforementioned species have an overall translucent paleyellow body colour with a greenish inner surface and white spots on the tips of the rhinophores, unlike the uniformly orangeyellow rhinophores of E. azorica sp. nov. In addition, E. flava and E. obtusa have a broader bright white line on the margins of the parapodia formed by white papillae, which may also be found in small clusters on the pericardial swelling. Also, white patches may appear scattered on the outer side of the parapodia of both species, not visible in E. azorica sp. nov.

The radula in E. azorica sp. nov. has shorter and wider bladelike teeth than those of E. flava and E. obtusa . Both E. azorica sp. nov. and E. flava show short denticulations on the cutting edge but differ in a lateral smooth edge present in E. flava . Likewise, E. obtusa possesses a different tooth shape with smooth edges without denticles or ‘serrulations’ (according to its original description).

Our molecular phylogenetic analyses confirm that E. obtusa from Indo-Pacific and Atlantic specimens of E. flava are genetically distinct in accordance with the analysis by Krug et al. (2016), and both species are different from E. azorica sp. nov. ( Fig. 1 View Figure 1 ). Indeed, the minimum uncorrected p -distances for COI between E. azorica sp. nov. and the sister-species E. flava were 10.6% (see Table 1 View Table 1 ) and 10.2% between E. azorica sp. nov. and E. obtusa (not shown).

Kingdom

Animalia

Phylum

Mollusca

Class

Gastropoda

Family

Plakobranchidae

Genus

Elysia

Darwin Core Archive (for parent article) View in SIBiLS Plain XML RDF