Neoferdina antigorum

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 : 44-46

Neoferdina antigorum n. sp

Figure 14 A–G

Etymology. This species is named for Evelyn and Emmanuel Antig who made the material available for study.

Diagnosis. This species is characterized by the presence of very few to absent strongly convex, bald abactinal plates but with a distinct round, bald patch on each superomarginal plate, which forms a regular, homogeneous series along the arm. A continuous granular tegument covers most of the body surface in this species. Abactinal plates are mostly homogeneous. This species has a minority of convex abactinal plates with bare patches and spinelets on distalmost inferomarginal plates. Bald patches are absent from the proximalmost inferomarginal plates ( Fig. 14 D).

Taxonomic comments. Neoferdina antigorum n. sp. displays similarities with two known species, N. japonica and N. insolita both of which lack or have very few of the strongly convex bare abactinal plates present in other Neoferdina species. Neoferdina japonica apparently possesses relatively few of these abactinal plates but differs in that it possesses transverse plate series across the arm, a character which is shared with N. cumingi and N. offreti but lacking in N. antigorum . Neoferdina japonica also apparently lacks bare regions on the first two superomarginals in each interradius.

The few convex bare regions present on the abactinal, the regular bare regions on the marginal plates, the spinelets on the distalmost inferomarginal plates, the granular tegument covering the proximal inferomarginals and tapering arms set Neoferdina antigorum n. sp. apart from Neoferdina insolita which show a rounded arm tip, lacks spinelets on the inferomarginal plates and have bare spots present on all inferomarginal plate surfaces.

Relative to N. offreti and N. cumingi , this species lacks the distinct transverse abactinal convex plates present on the arms. This species possesses a homogeneous series of superomarginal plates, which further distinguishes it from N. cumingi which has heterogeneously sized superomarginals. Among other Neoferdina species, N. antigorum n. sp. differs from Neoferdina glyptodisca in that the N. glyptodisca ’s abactinal surface is covered by low, mound-like (i.e. weakly convex) abactinal plates.

Occurrence. Balut and Camiguin Island, Philippine Islands, 80–200 m.

Description. Body strongly stellate (R/r= 3.5–3.9) with arms tapering, triangular in shape ( Fig. 14 A). Arms trapezoid in cross-section. Body thickness varies among individuals in the type series with CASIZ 218865 (R= 2.6 cm) displaying very flattened body versus CASIZ 218860 which is over twice as thick.

Abactinal plates primarily flattened to weakly convex, presenting a surface with very low relief ( Figs 14 A, B, C). Carinal and irregular radial plates convex, above abactinal surface with prominent bare patch ( Fig. 14 C). Bare central plates are variable with some displaying irregular alternating sequence with some showing an alternation of one to four tegument covered versus bald convex plates (e.g. Fig. 14 C) but irregularly some individuals in direct sequence ( Fig. 14 F). Central disk plates are flatter than those on arm plates which are weakly convex. Convex, bare plates mostly absent from disk ( Fig. 14 A). Only one individual observed had these on the disk, in all others, disk plates are flat and covered by granules. The presence of bare, convex plates is variable with some individuals displaying many (e.g. Fig. 14 F on CASIZ 218864) versus some which show relatively few (e.g. Fig. 14 A, C, CASIZ 218856). Carinal plates irregular in series with heterogeneous sizes and shapes varying along the series and alternating granule and bare patches ( Fig. 14 C). Abactinal plates number four to five across the arm base and continue up along arm tip to where superomarginals are abutting. Papulae single, present at abactinal plate corners, absent from interradial regions adjacent to superomarginals. Madreporite variable in shape, from triangular to polygonal. Sulci also variably weakly to strongly developed. No pedicellariae observed. Anal spines five or six, blunt and fingernail shaped, closed over aperture.

Marginal plates 16 to 26 from arm tip to arm tip. Marginal plates covered by granular tegument but with prominent circular to oval shaped dark bald patch. Superomarginals and inferomarginals show 1:1 correspondence with weakly expressed offset. Interradial inferomarginals covered by granular tegument ( Fig. 14 D) but distalmost half of arms with prominent bald patch, oval to circular in outline. Bare regions extend on some individuals (CASIZ 218864) from arm base proceeding irregularly along carinals, some convex plates alternating with small, granule covered plates whereas others (e.g. CASIZ 218856) display relatively few along the same series. Superomarginal and inferomarginals mostly elongate/elliptical in shape with interradial plates variably elongate to quadrate but with strongly concave contact with abactinal plates ( Figs. 14 B, C). Distalmost superomarginals, the two plates away from the terminus in the holotype and most of the paratypes, abutted over midline. One smaller sized individual (CASIZ 218864) with only one full pair in contact. Distalmost inferomarginals (the 2 to 4 plates away from the terminal) with short, thorny spinelet or low-lying pointed prominence emerging from the center of the inferomarginal plate ( Fig. 14 C). Terminal plate large, triangular, with smooth surface. No pedicellariae observed on marginal surfaces.

Actinal surface with three full series in chevron-like formation ( Fig. 14 E). A fourth irregular and incomplete series sits adjacent to the inferomarginal plates. Actinal plate surfaces completely covered by continuous fine granular tegument identical to the one present on abactinal and marginal surface. Actinal plates variable in shape, ranging from triangular, polygonal to quadrate, with more quadrate forms along arms. Actinal plate series do not extend completely along the arm and have completely pinched out at roughly halfway along the arm.

Furrow spines three per adambulacral plate, similar in morphology to those on anus. Furrow spines blunt, wide with bases covered by granular tegument which covers actinal surface. Adambulacral plates covered by granular tegument with no accessory structures ( Fig. 14 D, E). Oral plates with two blunt spines identical to furrow spines projecting into mouth and tightly articulated over oral region. As with the adambulacral plates, oral plates covered by granular tegument with no other spination or other accessories.

Although color in life is unknown, disk color on dry preserved specimens is orange-red and yellow-brown observed for the arms and actinal surfaces. Bare patches on marginal plates are distinctly dark brown to brick red while those on abactinal surface a lighter color similar to adjacent granulation on abactinal surface ( Figs. 14 A, B, C, D).

Material examined. Holotype: CASIZ 218855 ; Camiguin Island, Mindanao , Philippines, ~ 80 m ; 1 dry spec. R=3.7 r=1.0. Paratypes: Philippines. CASIZ 207276 ; Puerto Galera , Mindoro Province , Philippines, 13°31’19”N, 120° 59’41”E 79.2–94.5 m .; Coll. E. Jessup using closed circuit rebreather. MESO GAL 0 3,2015 Verde Island Passage Expedition; 1 wet spec. ; CASIZ 218856 ; Camiguin Island, Mindanao , Philippines, ~ 80 m; 1 dry spec., R=3.9 r=1.0 . CASIZ 218858 ; Balut Island , Philippines, 100–200 m; 1 dry spec., R=2.8 r=0.8 . CASIZ 218860 ; Balut Island , Philippines; Coll. Tangle net. no depth; 1 dry spec., R=3.5, r=0.9 . CASIZ 218862 ; Balut Island , Philippines, ~ 100–150 m; Coll. tangle net.;1 dry spec., R=3.7 r=1.0 ; CASIZ 218863 Balut Island , Philippines, ~ 100–150 m; Coll. tangle net; 1 dry spec., R=2.7 r=0.8 ; CASIZ 218864 Balut Island , Philippines, ~ 100–150 m; Coll. tangle net;1 dry spec.,R=2.3 r=0.6 ; CASIZ 218865 Balut Island , Philippines, ~ 100–150 m; Coll. tangle net;1 dry spec., R=2.6 r=0.6 ; CASIZ 218869 Balut Island , Philippines, 100–150 m; Coll. tangle net; 3 dry specs., R=3.6 r=1.0; R=3.4 r=0.5; R=1.4 . CASIZ 207928 , Sepok Wall , Maricaban Island, Luzon Island , Philippines. 13° 41' 23.9 N, 120° 49' 47.9 E, 6.1–22.9 m, Coll. M.G. Burke, 15 April 2016. 2016 Verde Island Passage Expedition. 1 wet spec. R=4.7 r=1.5 . CASIZ 207250 ; Boulders dive site, Verdes Island , Philippine Islands, 13°31’20”N 120°59’58”E, 91.4–106.7 m; Coll. Elliott Jessup, 9 Apr 2015; 1 wet spec. R=3.3, r=0.6. note specimen has four arms . CASIZ 202429 ; Sepok Wall , Maricaban Island, Batangas , Philippines, 13.69°N, 120.83°E; 1 wet spec. R=5.3, r=0.6 (unspined) . Solomon Islands. MNHN-IE-2013-6803, Solomon Islands, 6°51’S, 156°24’E, 277 m.; Coll. Bouchet, Waren & Samadi, IRD aboard N/ O Alis. SALOMON 2; 3 wet specs. R=1.9 r=0.5, R=1.7 r=0.5; R=1.8 r=0.5.

Figures

FIGURE 14. Neoferdina antigorum n. sp. A – E: Holotype, CASIZ 218855. Scale Bar = 3.5 mm. A. Abactinal surface. B. Lateral view showing bald patches on superomarginal plates and inferomarginal plate detail. C. Abactinal and superomarginal detail along the arm. D. Inferomarginal plate series and actinal surface. E. Oral surface. F. CASIZ Paratype 218864, Scale Bar = 2.5 mm. Detail on abactinal surface including carinal plates.