Bathyferdina aireyae

Mah, Christopher L., 2017, Overview of the Ferdina - like Goniasteridae (Echinodermata: Asteroidea) including a new subfamily, three new genera and fourteen new species, Zootaxa 4271 (1), pp. 1-72 : 12-14

Bathyferdina aireyae nov. sp.

Figure 2 A–G

Etymology. This species is named for Marie Airey (1977–2005), curatorial assistant in the Department of Invertebrate Zoology at the California Academy of Sciences.

Diagnosis. Bathyferdina is broadly similar to other ferdinine goniasterids sharing an adambulacral plate surface devoid of spinelets, enlarged/specialized granules or other accessories and in having a uniform granulate tegument which forms a continuous cover over the abactinal, marginal and actinal surface. Abactinal and marginal plates, when denuded, reveal low glassy bosses embedded on the surface of each plate. Bare spot, circular or quadrate. Body shape weakly stellate, generally with short arms and broad disk. Marginal plates blocky with thick disk.

Taxonomic comments. Although this species bears a superficial resemblance to Neoferdina insolita based on identification keys in Jangoux (1973) and Clark and Rowe (1971), comparison with Livingstone’s (1936) description reveals significant differences between the two species and between Bathyferdina and Neoferdina .

Bathyferdina does not fit within any of the known goniasterid genera and is presented as a new genus within the Ferdininae. Glassy bosses are present in B. aireyae n. sp. on the abactinal plates underlying the granular tegument ( Fig. 2 C) but were not located on any of the other species of Neoferdina examined. Further differences between Bathyferdina n. gen. and Neoferdina include a broader arm/disk R/r ratio (R/r=2.2–2.3) and homogeneously sized and shaped abactinal plates versus the more heterogeneous abactinal plates in Neoferdina . No convex or bare plates were present. Although both N. insolita and B. aireyae have a clear, bare region on the marginal plates, those in Bathyferdina n. sp. are more quadrate in shape ( Fig. 2 E) versus those in N. insolita which are more oval to round.

Bathyferdina aireyae n. gen., n. sp. has also been collected from a substantially deeper depth (91–408 m) relative to that of N. insolita (shallow, tropical reef). Neoferdina insolita has been observed displaying different colors whereas collected B. aireyae show a consistent brownish with dark red marginal plates.

Bathyferdina shares many characters with Kanakaster suggesting that the two are most likely sister taxa. Characters including glassy nodules on the abactinal plate surface, bare spots (albeit much smaller in Kanakaster ) on the superomarginal plates, a granular tegument covering abactinal, marginal and actinal surfaces, and consistently sized, relatively homogenous abactinal plates lacking strongly convex, enlarged bare plates. Both of these genera display characters which are most similar to some goniasterid genera, such as Ogmaster or Stellaster based on the granular surface covering.

One individual of this species, CASIZ 218870 from Balut Island in the Philippines was parasitized by a eulimid snail which had bored into the actinal surface.

Occurrence. Philippines, Vanuatu, Solomon Islands, New Caledonia. 91–408 m.

Description. Body stellate (R/r=1.7–3.2. mostly about R= 1.7–2.2 cm) with broadly curved interradial arcs. Arms triangular, disk broad. Radial regions on disk and arms weakly convex with depressed interradial areas ( Fig. 2 A). Smaller specimens more strongly stellate (R/r=3.25 at R= 1.3 cm) with more triangular arms. Larger individuals with broader disk and shorter arms.

Abactinal plates irregularly round to polygonal in outline with rounded edges. Surface flat. Plates, including the primary circlet plates, largest interradially on disk (approximately twice as large as adjacent plates). Carinal plates oval in outline extending along arm to point where superomarginals abut over midline. Abactinal and most of body surface covered by a dense, nearly continuous (save for bare regions on marginal plate and papular pores) cover of fine granules ( Fig. 2 B). Density approximately 10–15 granules along a 1.0 mm line. When plates are denuded, they reveal between five to 60 glassy bosses, flush with surface of each plate ( Fig. 2 C). Papular pores present primarily along radial regions on disk and arms, but absent interradially on disk. Larger granules, four to six, each about 4x the size of the other granules, flank each papular opening. Madreporite triangular to polygonal in contact with three to five plates. Anal opening at disk center with five to seven large (largest is ~1.0 mm length) granules.

Marginal plates 12–18 (identical for superomarginals and inferomarginals), per interradius, quadrate in outline ( Fig. 2 A). Greatest number of marginals per interradius observed in specimens with R>3.0. Superomarginals correspond 1:1 with inferomarginals with no offset contact. Marginals elongate (L>W) and weakly convex in cross-section. Marginal surface covered with dense continuous layer of granules contiguous with those on abactinal plates save for prominent quadrate-shaped bald patch on central surface of each plate. Superomarginals bald patch is larger, darkly colored, with bare, smooth surface, becoming larger distally along arm ( Fig. 2 D). Inferomarginal bald patch ( Fig. 2 E) approximately 1/4 the size of the bald area on its corresponding superomarginal. A minority of inferomarginal bald regions with a flat granule or tubercle present centrally on each region. As with the superomarginal bald regions, those present on the inferomarginals, also increase in size distally. These granules mostly present interradially or else, proximally on the arm. Distalmost two pairs of superomarginals abut over midline. Granular tegument on remaining areas of marginal plates continuous, with plate boundaries obscured by granules. Terminal plate broadly triangular.

Actinal intermediate plates in approximately four distinct rows in chevron formation ( Fig. 2 F). Individual plates quadrate to polygonal in shape ( Fig. 2 G). Larger and more quadrate in shape proximally becoming smaller and more irregular distally adjacent to the inferomarginals. As with other plate surfaces, actinal plates are covered by a continuous fine granular tegument similar to the ones present on the abactinal surface. Granules slightly coarser at contact between oral plates and proximal most point of actinal plates (i.e., the most internal chevron). No other accessories (e.g., spinelets, pedicellariae) observed.

Furrow spines quadrate to tooth shaped in outline, but present in a single series ( Fig. 2 G). Spines, primarily two, possibly three per plate, with complimentary alternating series along tube foot border. Small, round to irregular sized, granules, three to six, at base of each spine, coarser about two to three times the size of granules covering actinal surface.

No pedicellariae observed on disk, marginal or actinal surface.

Color in life is brown abactinal surface with dark, red-brown bare regions on marginal plates. Underside is a light tan.

Material examined. Holotype: CASIZ 185673 ; Balut Island, Mindanao , Philippines; 1 dry spec. R=2.5, r=1.3. Paratypes: CASIZ 185658 ; Balut Island, Mindanao, Philippines;1 dry spec., R=2.4 r=1.3. CASIZ 185667 ; Balut Island , Mindanao Philippines,1 dry spec., R=4.3, r=1.8. CASIZ 218867 ; Balut Island, Mindanao, Philippines, 150 m ; 1 dry spec., R=3.3, r=1.4. CASIZ 207252 ; Boulders dive site, Verde Island Passage , Philippines, 13° 31' 20.3" N, 120° 59' 57.5” E, 91.4–106.7 m ; Coll. Elliott Jessup, 9 Apr 2015; 1 wet spec. R=3.3, r=1.2. MNHN-IE-2013-5132; S Ile Anatom , Vanuatu, 20°20’S, 169°49’E, 360–408m; Coll. Bouchet & Richer de Forges, MUSORSTOM 8, 21 Sept 1996, DW 964;1 wet spec., R=2.4, r=0.9. MNHN-IE-2007-6337; Ellet Bank , New Caledonia, 22°52,3’S, 169°26,3’E, 100 m; Coll. EXBODI, DW 3866; 3 wet specs. (1 damaged), R=1.3, r=0.4; R=1.7, r=0.8; R=2.6, r=1.5. MNHN-IE-2007-126 ; Solomon Islands, 6°51’S, 156°24’E, 277 m .; Coll. Bouchet, Waren & Samadi, aboard N/ O Alis. SALOMON 2; 1 wet spec., R=3.0, r=1.3. CASIZ 219696 Balut Island , Philippines. 200 m. Coll. tangle net. 1 dry spec. R=4.3 r=2.0. Vouchers: CASIZ 218868 ; Balut Island, Mindanao, Philippines, 200–250 m (mixed multiple events); Coll. with tangle net; 6 dry specimens, R=3.4 r=1.8; R=3.0 r=1.7; R=3.1 r=1.7; R=3.2 r=1.5; R=2.8 r=1.3; R=2.5 r=1.3. CASIZ 218870 ; Balut Island, Mindanao, Philippines, 200–250 m.; Coll. with tangle net; 1 dry spec., R=2.5 r=1.3 (with eulimid snail).

Figures

FIGURE 2. Bathyferdina aireyae n. gen., n. sp. Paratype, CASIZ 218867. Scale Bar = 3.0 mm. A. Abactinal surface. B. Inset of abactinal surface showing granular tegument, plates. C. Abactinal surface, granules cleared showing glassy nodules on plate surface. D. Superomarginal plates showing bare spot on plate surface. E. Inferomarginal plates series showing bare spots on plate surface. F. Oral surface. G. Actinal surface showing oral region and furrow spines.