Vosmaeropsis recruta Cavalcanti, Bastos & Lanna, 2015

Vosmaeropsis recruta Cavalcanti, Bastos & Lanna, 2015 View in CoL

( Figs. 40 View FIGURE 40 , 41 View FIGURE 41 ; Table 16)

Synonyms: Vosmaeropsis recruta — Cavalcanti et al. 2015: 478.

Type locality: Arraial do Cabo , Rio de Janeiro State, Brazil .

Material examined: UFRJPOR6996, close to the Dart shipwreck, São Sebastião Island, Ilhabela, São Paulo State, Brazil, depth 4 m, coll. F. F. Cavalcanti, 30/XI/2008 . UFRJPOR6929, Parcel da Coroa , Búzios Island, Ilhabela, São Paulo State, Brazil, depth 6 m, coll. F. F. Cavalcanti & V. Padula, 02/XII/2008 . UFRJPOR7045, Costa do Aquário , Búzios Island, Ilhabela, São Paulo State, Brazil, depth 12 m, coll. F. F. Cavalcanti, V. Padula & R. Berlinck, 05/XII/2008 .

Colour: Beige in life and white in ethanol ( Fig. 40A View FIGURE 40 ).

Morphology and anatomy: Sponge tubular, with new branches growing near the base ( Fig. 40A View FIGURE 40 ). The osculum is apical and surrounded by a crown of trichoxeas ( Fig. 40A, B View FIGURE 40 ). The external surface is very hispid because of several projecting diactines and trichoxeas. Aquiferous system leuconoid, with subcortical lacunae. However, in some sections, it resembles a sylleibid organisation, with wide exhalant canals ( Fig. 40C View FIGURE 40 ).

The oscular crown of trichoxeas is supported by T-shaped triactines and tetractines ( Fig. 40B View FIGURE 40 ). The cortical skeleton is composed of tangential triactines, diactines obliquely arranged, and few trichoxeas that occasionally form discrete tufts ( Fig. 40D View FIGURE 40 ). The subcortical skeleton is composed of pseudosagittal triactines ( Fig. 40D View FIGURE 40 ). The choanosomal skeleton is disorganised but shows traces of articulation, since many of the tubar triactines point their unpaired actine to the cortex ( Fig. 40C, E View FIGURE 40 ). The subatrial skeleton is formed by triactines, with the long unpaired actine crossing a large part of the choanosome ( Fig. 40C, F View FIGURE 40 ). Only one subatrial tetractine was found. The atrial skeleton is mainly composed of triactines, but tetractines are also common ( Fig. 40G View FIGURE 40 ).

Spicules ( Table 16):

Trichoxeas: Long, thin, cylindrical, sometimes curved, with sharp tips. The oscular trichoxeas are thicker than typical trichoxeas.

Diactines: Large, curved, with the distal tip lanceolate and the proximal one thicker ( Fig. 41A–C View FIGURE 41 ). Size: 1,319.5 (±604.6)/46.1 (±16.3) µm.

Cortical triactines: Sagittal. Actines are conical to slightly conical, with sharp tips. The unpaired actine is straight and longer than the paired ones, which are almost straight, undulated and sometimes unequal in length ( Fig. 41D View FIGURE 41 ). Size: paired—152.7 (±31.2)/10.5 (±1.5) µm; unpaired—172.8 (±45.8)/10.1 (±1.5) µm.

Subcortical triactines: Pseudosagittal. Actines are sligthly conical, with sharp tips. All actines are frequently undulated ( Fig. 41E View FIGURE 41 ). Size: paired 1—254.3 (±25.9)/13.2 (±2.8) µm; paired 2—157.7 (±35.5)/11.9 (±2.2) µm; unpaired—131.8 (±25.2)/12.4 (±2.5) µm.

Choanosomal triactines: Slightly sagittal. Actines are sligthly conical, with sharp tips, and frequently undulated. The paired actines are curved outwardly and similar in length to or shorter than the unpaired one ( Fig. 41F View FIGURE 41 ). Size: paired—211.3 (±50.5)/15.5 (±2.3) µm; unpaired—229.0 (±43.9)/16.7 (±2.6) µm.

Subatrial triactines and tetractines: Sagittal. Basal actines are sligthly conical to cylindrical, with sharp tips, and can be undulated. The unpaired actine is much longer than the paired ones. They are as thin as the subcortical and choanosomal triactines ( Fig. 41G View FIGURE 41 ). The only tetractine observed had a short, conical and sharp apical actine. Triactines size: paired—173.3 (±30.6)/14.6 (±2.5) µm; unpaired—281.9 (±57.7)/15.9 (±2.1) µm.

Atrial triactines and tetractines: Sagittal. Basal actines are slightly conical to cylindrical, with blunt to sharp tips, and can be undulated. The unpaired actine is straight and shorter (more common) or similar in length to the paired ones, which are generally slightly curved ( Fig. 41H, I View FIGURE 41 ). The apical actine of the tetractines is short, conical, smooth and sharp. Triactines size: paired—206.2 (±46.1)/12.3 (±1.4) µm; unpaired—138.1 (±65.0)/12.4 (±1.3) µm. Tetractines size: paired—181.2 (±37.6)/13.6 (±2.0) µm; unpaired—157.3 (±47.3)/13.1 (±2.2) µm; apical—44.0 (±9.6)/9.1 (±1.4) µm.

Ecology: Unlike the type specimens from Arraial do Cabo, which were found on artificial (plastic) substrates, the specimens from Ilhabela were collected on natural rocky substrates, in burrows or associated with algae .

Geographic distribution: Southeastern Brazil ecoregion—Arraial do Cabo, Rio de Janeiro State ( Cavalcanti et al. 2015); São Sebastião and Búzios Islands (Ilhabela), São Paulo State (present study), Brazil.

Remarks: Our specimens closely match the diagnostic features of V. recruta , originally described and (until now) only known from the neighbouring state of Rio de Janeiro. There is only a minor difference concerning the size of the diactines, which are, on average, slightly longer and thicker [1,319.5 (±604.6)/46.1 (±16.3) µm] than those of the holotype [905.9 (±418.0)/37.9 (±7.4) µm]. Additionally, we found a single subatrial tetractine (similar to the subatrial triactines, but with a short apical actine), a spicule type not mentioned in the original description and probably very rare in this species. Thus, the distribution of V. recruta is expanded to São Paulo State, although it remains restricted to the Southeastern Brazil ecoregion.

The C-LSU sequences of V. recruta were identical to that of an unidentified specimen of Heteropiidae sp. from St. Helena Island, generated by Alvizu et al. (2018), and they formed a strongly supported clade (BS = 100%). As no formal description of this St. Helena specimen has been provided, a revision is required to confirm whether it corresponds to V. recruta .