Exsuperantia archipelagus, Carvalho & Pisera, 2019

Carvalho, Francisca C. & Pisera, Andrzej, 2019, Revision of the genus Exsuperantia Özdikmen, 2009 (Tetractinellida: Phymaraphiniidae) with description of a new species from the Atlantic Ocean, Zootaxa 4613 (1), pp. 135-151 : 140-141

Exsuperantia archipelagus sp. nov.

Figures 1 –4; Table 3

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Synonymy. Racodiscula clava sensu Topsent (1892, 1904 , 1928); Exsuperantia sp. Carvalho et al. (2015).

Type locality. Terceira island, Azores archipelago, Portugal.

Type material. Holotype. MNHN DT-782/1 (dry specimen), locality: Terceira island, Azores archipelago, Por- tugal (38º52’50’’N, 27º23’05’’W), depth: 599 m . Paratypes. MNHN DT-782/2 (dry specimen), locality: Terceira island, Azores archipelago, Portugal (38º52’50’’N, 27º23’05’’W) depth: 599 m ; DOP1976 (specimen preserved in 90% ethanol), locality: Azores Bank, Azores archipelago, Portugal (38º05’59’’N, 29º08’59’’W), 168–594 m depth.

Additional material. Exsuperantia archipelagus sp. nov.: DOP 5883/6212/6248/6255, Azores archipelago; HBOM 003:02023 (BMR 29-V-91 -3-003), Madeira, HBOM 003:00660 (BMR 09-VI-91 -4-008), Canaries (see table 1 for more details).

Comparative material examined. Exsuperantia clava Schmidt 1879 — Syntype MCZ 6436 (orig. 275), Gulf of Mexico.

External morphology. Columnar to ficiform sponges, that can possess lateral protuberances or branches ( Fig. 1 ). Small, 20–30 mm tall and 10–20 mm thick, attached to the substrate by the entire base. Surface is smooth, with marked water canals on the surface of the choanosomal skeleton. Oscules or pores are not visible to the naked eye. Color is beige to whitish in ethanol and when dry.

Skeleton. The ectosome is composed by a layer of overlapped phyllotriaenes ( Figs. 2 A–B), numerous acanthomicroxeas and acanthorhabds, and some amphiasters. Pores are surrounded by these microscleres. The choanosome has regular trider-type desmas with smooth and/or tuberculated tubercles; the sculpture of the tubercles is related to the stage of formation of the desma: smooth tubercles in earlier stages and tuberculated when older; the extremities of the desmas also varies, spine-like and smooth when young, or with a tubercle on the top when older ( Figs. 2 C–H, Fig. 3 ). Subtylostyles to tylotes are transverse to the surface, and cross both parts of the skeleton. Acanthorhabds and acanthomicroxeas are very abundant and spread through the entire skeleton; amphiasters are few and dispersed.

In addition, we have found some spicules with a strange appearance in the lower part of the sponge in the paratype DOP1976 ( Fig. 3D ). They resemble irregular disco- to phyllotriaenes with a strong sculpture that have been developed in the lower part and merged with the desma skeleton. This skeleton formation, previously observed in other lithistid demosponges, may have the purpose of consolidating the basal skeleton of the sponge.

Figures

FIGURE 1. Habitus of Exsuperantia archipelagus sp. nov. A: Holotype MNHN DT 782/1, B: Paratype MNHN DT 782/2, C: Paratype: DOP1976 (scale 1 cm).

FIGURE 2. Exsuperantia archipelagus sp. nov. Holotype MNHN DT 782/1, from Azores. A: Top surface of the sponge with phyllotriaenes (scale 1 mm), B: details of overlapping phyllotriaenes in the ectosome (scale 200 µm), C–D: upper surface of the choanosomal skeleton composed of triders located in the upper part/top of the sponge (growing edge) (scale 1mm and 200 µm, respectively), E–F: choanosomal triders located in the lower part/or near the base of the sponge (scale 500 µm and 200 µm, respectively), G: young trider desma with smooth tubercles (scale 200 µm), H: old trider with distinct tuberculation of the tubercles and detail of the zygome (articulation) (scale 100 µm).

FIGURE 3. Exsuperantia archipelagus sp. nov. Paratype DOP 1976, from Azores.A: surface of the choanosomal skeleton from the top of the sponge (scale 500 µm), B: surface of the choanosomal skeleton from the base of the sponge (scale 500 µm), C: young trider (lower part), and a phyllotriaene (upper left) (scale 200 µm), D: surface of the chaonosomal skeleton with irregular triders in the basal part of the sponge (scale 220 µm), E: detail of young and less regular trider and its zygome (scale 100 µm), F: detail of older trider (scale 200 µm).