Aeginella corallina Zettler & Freiwald & Guerra-García 2018, sp. nov.

Aeginella corallina sp. nov.

(Figs 2–6)

Type material. Holotype, mature male, 8.9 mm (used for description and drawings of lateral view, antennae, gnathopods, mouthparts, pereiopods 3–7 and abdomen) (vial: ZMB 31309), Scary mound at 374–375 m water depth at 9.82286°S and 12.77381°E, South Atlantic off Angola, associated to hexactinellid sponges (Sympagella sp. and Aphrocallistes sp.) within a Lophelia pertusa gallery, leg. 22nd January 2016.

Paratype “1”, mature female, 7.3 mm (used for description and drawings of lateral view, antennae, gnathopods, mouthparts, pereiopods 3–7 and abdomen) (vial: ZMB 31310), collected together with the holotype.

Paratype “2”, immature male, 6.2 mm (vial: ZMB 31311), part of the bulk from ROV dive and could not be associated to a specific subsample, same data as holotype.

Paratype “3”, mature male, 8.6 mm (vial: ZMB 31312), Valentine Mound at 500 m water depth at 9.72833°S and 12.71460°E, South Atlantic off Angola, associated to a hydroid which was attached to a dead Madrepora branch, 17th January 2016.

Type locality. Scary Mound at 374–375 m water depth at 9.82286°S and 12.77381°E, South Atlantic off Angola.

Diagnosis. Head with a dorsal acute projection. Pereonite 1 smooth. Pereonite 2 with a pair of dorsal acute projections anteriorly, one projection distally, and lateral acute projections (one in each side) near the coxa of gnathopod 2. Basis and ischium of gnathopod 2 with a distal projection. Propodus of gnathopod 2 very setose in males, provided with one proximal projection and 2 large distal projections. Distal article of the mandibular palp with 4 or 5 setae.

Etymology. The species is named with reference to the cold-water corals habitat in which it was found.

Description. Holotype male (8.9 mm).

Lateral view (Figs 2 and 3). Head with dorsal acute projection. Pereonite 1 lacking projections. Pereonite 2 with a pair of dorsal acute projections anteriorly, and one projection distally, and lateral acute projections (one in each side) near the coxa of gnathopod 2. Pereonite 3 with ventral lateral projections (one in each side of the pereonite), two medial and 1 distal projections. Pereonite 4 similar to pereonite 3 but lacking distal projection. Pereonite 5 with two projections proximally and another acute projections distally. Pereonite 6 with two dorsal projections. Pereonite 7 smooth.

Gills (Figs 2 and 3). Elongated, length about 1.5 times its width.

Mouthparts (Fig. 4). (Left mandible and upper lip lost during dissection; left mandible figured for the paratype 1 female, see figure 6) Right mandible with trituritive molar, moderately developed and dentate marginally. Threearticulate palp; medial article provided with two setae; distal article of palp the longest, with a setal formula 1-x- 1, being x=3 (although it could be considered as a formula 1-x- 0 with x=4); incisor five-dentate, lacinia mobilis looking like a blade, followed by two more blades; no sign of molar flake. Lower lip without setae; inner lobes with rounded margin. Maxilla 1 outer lobe carrying seven spines distally serrate, palp two-articulate, distal article with four apical setae and three medial setae. Maxilla 2 inner lobe slightly shorter than outer lobe, both with abundant setae apically. Maxilliped inner plate oval, carrying two short spines and several plumose setae; outer plate oval and elongate, with two apical plumose setae and several media non-plumose setae; palp four-articulate, scarcely setose, distal article (dactylus) slightly curved.

Antennae (Figs 2, 3 and 5). Peduncle of antenna 1 of the same length that head and pereonites 1 and 2 combined; second article the longest; flagellum with 16 articles. Antenna 2 as long as the peduncle of antenna 1; proximal peduncular article with a well-developed acute gland cone distally; swimming setae absent; flagellum two-articulate.

Gnathopods (Figs 2, 3 and 5). Gnathopod 1 basis of the same length than the combination of ischium, merus and carpus; grasping margin of propodus smooth; two proximal grasping spine, dactylus bifid distally. Gnathopod 2 inserted on the anterior end of pereonite 2; basis shorter than pereonite 2, with a distal acute projection; ischium rectangular with a distal acute projection; merus rounded; carpus short and rectangular; palm of gnathopod 2 propodus very setose, with proximal projection provided with one grasping spine, and two large projections distally.

Pereopods (Figs 2, 3 and 5). Pereopod 3 and 4 absent. Pereopods 5-7 increasing in robustness, attached to the distal end of pereonites, six-articulate, setose and provided with two grasping spines proximally.

Penes (Fig. 4) large, situated laterally, distinctive, oval, length ca. 2 times its width.

Abdomen (Fig. 4) with a pair of uniarticulate appendages situated laterally, two lateral lobe and a single dorsal lobe provided with two plumose setae.

Paratype female “1” (7.3 mm) (Figs 3, 6 and 7). Similar to the male except for the following characteristics: presence of oostegites on pereonites 3 and 4, both scarcely setose; pereonites 3 and 4 lacking acute dorsal projections; pereonite 4 lacking proximal lateral acute projections; gills smaller than in male and gills on pereonite 3 larger than gills on pereonite 4; gnathopod 2 propodus smaller and less setose than in male, distal projections scarcely developed; abdominal appendages smaller than in male and less setose.