Ascandra spalatensis, Klautau, Imesek, Azevedo, Plese, Nikolic & Cetkovi, 2016

Klautau, Michelle, Imešek, Mirna, Azevedo, Fernanda, Pleše, Bruna, Nikolić, Vedran & Ćetković, Helena, 2016, Adriatic calcarean sponges (Porifera, Calcarea), with the description of six new species and a richness analysis, European Journal of Taxonomy 178, pp. 1-52 : 10-11

Ascandra spalatensis sp. nov.

urn:lsid:zoobank.org:act:A5DC68F2-D856-4492-AF50-E5F6A1A7FD8A

Fig. 3 ; Table 3

Etymology

From the type locality. Spalato is an Italian name for Split, the largest city of the Dalmatian region.

Material examined

Holotype

ADRIATIC SEA: near Zadar, 44°08'14.8" N, 15°12'38.2" E, 1 m, collected by V. Nikolić, 13 Feb. 2011 (PMR-17806 = UFRJPOR 7540, in ethanol).

Colour

White in ethanol.

Description

The sponge is small, only a fragment, but it is possible to recognise large and loosely anastomosed tubes, typical of Ascandra ( Fig. 3A ). The skeleton is composed of triactines and a few tetractines ( Fig. 3B ).

Spicules ( Table 3)

TRIACTINES. Regular (equiangular and equiradiate), but there are also subregular (sagittal) spicules. Actines are cylindrical to slightly conical with sharp tips ( Fig. 3C ). Size: 90.5/8.0 µm.

TETRACTINES. Regular (equiangular and equiradiate) or subregular. Actines are strongly conical with sharp tips ( Fig. 3D ). The apical actine is shorter than the basal ones, thick, conical, sharp and smooth ( Fig. 3E ). Size (basal actine): 99.4/12.0 µm; 74.3/ 10.8 µm (apical actine).

Ecology

The specimen was collected on a shaded, vertical hard bottom.

Remarks

The genus Ascandra is so far composed of 13 species: A. falcata Haeckel, 1872 ; A. ascandroides ( Borojević, 1971) ; A. atlantica (Thacker, 1908) ; A. biscayae ( Borojević & Boury-Esnault, 1987) ; A. brandtae (Rapp et al., 2013) ; A. contorta (Bowerbank, 1866) ; A. corallicola (Rapp, 2006) ; A. crewsi Van Soest & De Voogd, 2015 ; A. densa Haeckel, 1872 ; A. kakaban Van Soest & De Voogd, 2015 ; A. loculosa (Dendy, 1891) ; A. minchini Borojević, 1966 ; and A. sertularia Haeckel, 1872 .

In 2013, Klautau et al. proposed the following diagnosis for Ascandra : “ Calcinea with loosely anastomosed tubes. Tubes are free, at least in the apical region. The skeleton contains regular (equiangular and equiradiate) or sagittal triactines and tetractines. Tetractines are the main spicules, occurring at least in the same proportion as the triactines. They have very thin (needle-like) apical actines. Diactines may be added. Asconoid aquiferous system.”

After the discovery of A. spalatensis sp. nov., we propose here an emendation to this diagnosis: “ Calcinea with loosely anastomosed tubes. Tubes are free, at least in the apical region. The skeleton contains regular (equiangular and equiradiate) or sagittal triactines and tetractines. The apical actine is very thin (”

needle-like) or very thick at the base. Diactines may be added. Asconoid aquiferous system. Our new species is a very typical Ascandra , with apically free, loosely anastomosed tubes. Its skeleton is very similar to that of A. ascandroides , i.e., composed of triactines and tetractines, the former being more abundant than the latter and the apical actine of the tetractines being very thick at the base. Both species, however, can be differentiated by the size of the spicules ( A. ascandroides - triactines: 90–130(±20)–163 /13(±2); small tetractines: 107.5–164.5(±35)–260/16.5(±2.8); large tetractines: 193.8–313.1(±63.2)– 418.2/39.8(±8.2)). Moreover, A. ascandroides has two categories of tetractines and A. spalatensis sp. nov. only one. In our ITS tree ( Fig. 16 ) this species is well nested within the Ascandra clade, with high support values in both, Bayesian and ML analyses.

Figures

Fig. 3. Ascandra spalatensis sp. nov., holotype (PMR 17806 = UFRJPOR 7540). A. Specimen in ethanol. B. Tangential section. C. Triactines. D. Tetractines. E. Apical actine of a tetractine.

Fig. 16. Maximum likelihood (ML) tree based on ITS1-5.8S-ITS2 rDNA sequences of Calcinea. Bayesian posterior probabilities (PP) and bootstrap values (BS) are given near the branches (PP/BS; when>0.50). Adriatic specimens are written in bold; *Adriatic specimens obtained during this study; **Mediterranean specimens of Borojevia cerebrum; ***Brazilian specimens of Clathrina conifera.