Borojevia moana, Lopes & Pérez & Klautau, 2024

Lopes, Matheus Vieira, Pérez, Thierry & Klautau, Michelle, 2024, Cave-dwelling calcareous sponges (Porifera: Calcarea) from the Marquesas Islands, French Polynesia, Zoological Journal of the Linnean Society (zlae 138) 202 (3), pp. 1-29 : 7

Borojevia moana sp. nov.

( Figs 5, 6; Table 2)

Zoobank registration: urn:lsid:zoobank.org:act:7F25DF3B-A045-47C7-8EDC-ED25B5EFC60A .

Type species: Ascaltis cerebrum Haeckel, 1872 .

Diagnosis: White Borojevia , cormus composed of regular and tightly anastomosed tubes. Multiple water-collecting tubes present. Skeleton composed of tripods, triactines, and tetractines. Apical actine of the tetractines either smooth or with five to nine rows of spines.

Etymology: From ‘Moana’ (Ocean in Maori), for the oceanographic expedition Pakaihi i te Moana, which collected the sponges published here

Type material: Holotype: French Polynesia, Marquesas Islands, Motu Iti Island : UFRJPOR 7524 , lava tunnel (8°40.6 ʹ S, 140°37.2 ʹ W), 8 m depth, 25.i.2012, coll. T. Pérez, field number MQ27-GR-TP2.

Colour: White alive and in ethanol ( Fig. 5A, B).

Description: Sponge massive, with cormus formed by regular and tightly anastomosed tubes ( Fig. 5A–C). Outer surface smooth and, in some regions, folded. Various water-collecting tubes emerge from conical projections on the surface ( Fig. 5B). On the thicker parts of the cormus, there is a space lined by the walls of internal tubes, giving the appearance of an atrial cavity, but lacking membrane around it ( Fig. 5C). Aquiferous system asconoid. Skeleton typical of the genus, with rare tripods present on the surface of the external tubes, triactines, and tetractines ( Fig. 5D).

Spicules ( Fig.6; Table 2)

Tripods: Regular to subregular. Actines conical, stout, and undulated, with blunt to sharp tips. They resemble large triactines and are very rare ( Fig. 6A). Size (UFRJPOR 7524): 63.4 (±5.5)/8.4 (±1.1) µm.

Triactines: Regular. Actines slightly conical to conical, with blunt to sharp tips ( Fig. 6B). Size (UFRJPOR 7524): 56.6 (±6.3)/6.8 (±1.0) µm.

Tetractines: Regular. Actines slightly conical to conical, with blunt to sharp tips ( Fig. 6C, D). Apical actine slightly conical, smooth, or with well-developed spines organized in five to nine rows ( Fig. 6D). It is straight and sharp. Size (UFRJPOR 7524): 56.9 (±5.1)/6.4 (±1.1) µm (basal); 53.1 (±9.2)/4.9 (±0.7) µm (apical).

Ecology: Large patch of the specimen was encrusting a boulder ( Fig. 5A).

Geographical distribution: Currently known only from the type locality. Ecoregion : Marquesas .

Remarks: Considering the currently accepted Borojevia species, those with a cormus formed by regular and tightly anastomosed tubes, and skeleton composed of tripods, triactines and tetractines are: Borojevia aspina ( Klautau et al., 1994) , Borojevia brasiliensis ( Solé-Cava et al., 1991) , Borojevia croatica Klautau et al., 2016 , Borojevia crystallina Fontana et al., 2018 , and Borojevia trispinata . Borojevia aspina and Borojevia trispinata can be distinguished from our new species mainly by the spine pattern on the apical actines of tetractines. While the apical actine of Borojevia moana sp. nov. varies from smooth to spiny, with long spines displayed in many rows, the apical actine of Borojevia aspina is smooth or the spines are vestigial. Borojevia trispinata has a single row with three spines only. The size and abundance of the tripods also differentiates Borojevia moana sp. nov. [63.4 (±5.5)/8.4 (±1.1) µm; with rare tripods] from Borojevia croatica [102.6 (±10.0)/11.9 (±1.5) µm; with common tripods ( Klautau et al. 2016)], and Borojevia crystallina [169.2 (±15.5)/21.9 (±2.5) µm; with numerous tripods ( Fontana et al. 2018)].

Borojevia moana sp. nov. is morphologically different from Borojevia tubulata by the encrusting growth form of the new species, spines in rows of five to nine, and frequently shorter spicules (Table 2), while Borojevia tubulata is tubular, has spines in rows of three, and has larger spicules. Nevertheless, in our molecular analysis (C-LSU), Borojevia moana sp. nov. grouped, with low bootstrap (<60%), with Borojevia tubulata from Seychelles (ZMAPOR 12435). In the original description, authors mentioned morphological variation among the specimens of Borojevia tubulata from Maldives (holotype: RMNHPOR 10158) and Seychelles, but they considered these differences as intraspecific variability ( Van Soest and De Voogd 2018). These differences are mainly in colour (the specimens of Borojevia tubulata from Maldives are white to cream, while the Seychelles’ specimen is yellow) and spicules (sagittal triactines and tetractines are present in the Maldives’ specimens and absent in the Seychelles’ specimen). Moreover, we noticed that the spines of the apical actines are in the middle of the actine in the holotype of Borojevia tubulata , while in the Seychelles’ specimen they are only on the distal portion of the actine ( Van Soest and De Voogd 2018: 30, 32). For that reason, the Seychelles’ specimen most likely represents a different species from Borojevia moana sp. nov. and Borojevia tubulata . Hence, we assign it as Borojevia aff. tubulata .

The most similar species to Borojevia moana sp. nov. is the Brazilian species Borojevia brasiliensis . However, the spines in the apical actine of the tetractines of Borojevia brasiliensis are very short, while in Borojevia moana sp. nov. they are well developed. Besides, the actines of the triactines and tetractines of Borojevia brasiliensis are conical with blunt tips, while in the new species they are slightly conical and blunt to sharp. Overall, spicules of Borojevia brasiliensis are larger and thicker [holotype of Borojevia brasiliensis — tripods: 81.0 (±8.2)/11.0 (±1.7) µm; triactines: 78.2 (±10.6)/10.8 (±1.5) µm; tetractines: 75.3 (±10.0)/10.4 (±1.3) µm (basal); 36.4 (±9.4)/8.0 (±2.2) µm (apical) ( Klautau and Valentine 2003). Borojevia moana sp. nov. —tripods: 63.4 (±5.5)/8.4 (±1.1) µm; triactines: 56.6 (±6.3)/6.8 (±1.0) µm; tetractines: 56.9 (±5.1)/6.4 (±1.1) µm (basal); 53.1 (±9.2)/4.9 (±0.7) µm (apical)]. Moreover, our molecular results clearly show that they are different evolutive lineages ( Figs 2, 3).