Corvoheteromeyenia sanidastosclera, Pinheiro & Silva & Calheira, 2015

Pinheiro, Ulisses, Silva, Carlos & Calheira, Ludimila, 2015, Sanidaster in freshwater sponges: an unexpected spicule for the birotuled Genus Corvoheteromeyenia Ezcurra de Drago, 1979, Zoosystema 37 (3), pp. 449-456 : 453-456

Corvoheteromeyenia sanidastosclera n. sp. ( Figs 2C, D ; 5 )

TYPE LOCALITY. — São Francisco Basin , Paulo Afonso Municipality, Bahia State, Brazil, in tanks fish farm. TYPE SPECIMENS. — Holotype. UFPEPOR1105, São Francisco

Basin, Paulo Afonso Municipality, Bahia State, Brazil, in tanks fish farm tanks, (09°22’30’’S, 38°13’58’’W), C. Silva coll., 06.IV.2010. Paratypes. UFPEPOR1113, UFPEPOR1116, UFPEPOR1132 and MNHN.DCL4110, São Francisco Basin, Paulo Afonso Municipality, Bahia State, Brazil, in fish farm tanks, (09°22’30’’S, 38°13’58’’W), C. Silva coll., 06.IV.2010.

DIAGNOSIS. — Sponge encrusting to slightly massive, with megascleres that are exclusively microspined oxeas; pseudobirotuled microscleres present in two distinct types; gemmuloscleres present as sanidasters inserted radially in the gemmules.

ECOLOGY. — The specimens were collected in clear waters of artificial environment, in fish farm tanks walls measuring 1.5 m ³ and 800 m ³, that are supplied with water from São Francisco River, with depth ranging from 10 cm to 1 m.

ETYMOLOGY. — The specific epithet refers to of morphology of the sponges’ gemmuloscleres: sanidaster.

DESCRIPTION OF HOLOTYPE

UFPEPOR1105 is encrusting, forming a thin layer on the substrate. Colour is dark green in vivo and beige in ethanol. Megascleres acanthoxea (234.2-269.1-310.7 / 9.7-12.7- 19.1 Μm), microscleres with two types of pseudobirotules: type 1 (short shaft), (11.9-18.4-26.3 / 2.4 // 3.6-4.9-7.2 Μm) more abundant than type 2 (long shaft), (31.1-48.6-71.7 / 2.4-3.9-4.8 Μm), sanidaster gemmuloscleres (71.7-82.8-95.6 / 4.8-7.3-19.1 // 3.2-6.3-9.7 Μm), gemmules (406.3-466.4- 501.9 Μm).

DESCRIPTION

Corvoheteromeyenia sanidastosclera n. sp. is characterized by presence of sanidaster gemmuloscleres (acanthostrongyles with tuberculate spines, Fig. 5E ). The shape of this sponge ranges from encrustant to slightly massive, not exceeding 1 cm of thickness. Colour dark green in vivo and becoming light green ( Fig. 2C, D ) or beige in ethanol. Consistency soft, easily torn. Gemmules distributed throughout the sponge but concentrated near the substrate.Megascleres fusiform, slightly curved oxeas (225.4-307.7-373.5 / 6.4-12.8-19.3 Μm), smooth or with recurved sparse microspinations, ranging from simple to compound ( Fig. 5A, B ). Pseudobirotuled microscleres of two types ( Fig. 5C, D ): type 1, (11.9-18.9-35.4 / 2.4-3.0-3.2 // 3.6-6.2-9.7 Μm) most common, with three or four large hooks forming rotules and a short shaft that can be smooth or spined ( Fig. 5C ); and type 2, (31.1-56.6-90.2 / 2.4-5.9- 9.7 Μm), less common with more discreet hooks forming rotules and a longer shaft than type 1, with simple to compound microspines distributed equitably along the shaft ( Fig. 5D ).

Gemmuloscleres sanidasters (51.5-80.9-96.6 / 4.8-7.4-19.1 // 3.2-6.1-9.7 Μm), inserted radially on the theca of gemmules ( Fig. 5H ) with tuberculated spines distributed along the shaft which often have secondary small spines near the tips. Spines along the gemmulosclere are perpendicular to the shaft and might be spirally arranged; spines near the tips are often oblique to the shaft. Occasionally, sanidasters have spines near the tips clustered end resembling a birotule but with the shaft exceeding the rotule ( Fig. 5E ). Gemmules (406.3-552.7-627.9 Μm) abundant, greenish, spherical, free or normally located in the basal part of sponge ( Fig. 5F ). Foramen single and circular ( Fig. 5G ). Gemmular theca tri-layered ( Fig. 5H ); outer layer with emerging tips of sanidaster; pneumatic layer well developed, with network of regular spongin fibers; gemmuloscleres radially embedded; inner layer well developed with compact spongin.

REMARKS

The sanidaster gemmuloscleres found here could be interpreted as malformations due to environment conditions. Mysing-Gubala & Poirrier (1981) observed malformations in gemmuloscleres of Ephydatia fluviatilis (Linnaeus, 1759) when submitted to cadmium (Cd) and mercury (Hg) in experimental conditions. In this case, 33% and 50% of gemmuloscleres were malformed when the sponges were exposed at Cd and Hg respectively. Although, in Corvoheteromeyenia sanidastosclera n. sp. 100% of gemmuloscleres are sanidasters, and we do not believe that this morphology of spicules could be a result of a possible chemical compounds exposure in the environment. Although, we did not measured the chemical composition of the water, we believe that this water has not been contaminated by heavy metal, since these fish farm tanks are used for human feeding. Besides, we collected Corvoheteromeyenia heterosclera in the same locality (specimens above), which have 100% birotule gemmuloscleres ( Fig. 2C ).

Corvoheteromeyenia sanidastosclera n. sp. is characterized by the presence of sanidaster gemmoscleres which differentiates it from C. australis and C. heterosclera that have birotuled gemmuloscleres.

Except for experimental conditions in Ephydatia fluviatilis explained above, sanidaster had been reported just once in freshwater sponges by Volkmer-Ribeiro & Watanabe (1983) in the description of Sanidastra yokotonensis Volkmer-Ribeiro & Watanabe, 1983 . In the occasion, the authors interpreted this find as a possible phylogenetic relationship with the family Latrunculiidae Topsent, 1922 (order Poecilosclerida ) and reinforced the hypothesis of polyphyletic origin of freshwater sponges from different marine sponges stocks.In subsequent works, Manconi & Pronzato (1996, 2002) reported Sanidastra yokotonensis from Mediterranean.They disagree with polyphyletic’s hypothesis of Volkmer-Ribeiro & Watanabe (1983). Additionally, they didn’t use the term “sanidaster” for the gemmuloscleres, because they believe that these spicules are a freak oxea.

On the other hand, Samaai & Kelly (2002) provided an excellent illustration, which shows that the sanidaster spicules are found in different phylogenetic taxa. In this sense, we believe that the spicule sanidaster has had a homoplastic origin and do not represent a character with a phylogenetic signal. Like other spicules, as “birotule” which is used to unrelated taxa (for example, family Iotrochotidae Dendy, 1922 marine sponges, and Spongillidae Freshwater sponges). Thus, there is no sense in using sanidasters only to marine sponges. Here we prefer to use the term “sanidaster” to describe the morphology of the spicule.

The new species shares with other species of Corvoheteromeyenia megascleres oxeas, and two categories of pseudobirotuled microscleres, which allowed this species to be allocated in this genus. Ezcurra de Drago (1979) reinforces that gemmulosclere is the most important diagnostic character in Corvoheteromeyenia , when differentiated C. australis and C. heterosclera by the former present variation in the shape and size of rotules against stable shape and size of rotules in the latter. In this way, C. sanidastosclera n. sp. do not have rotules in its gemmuloscleres. Beside, the gemmuloscleres of the new species have spines longer than others species ( Table 1) and with different morphology, with tuberculate spines in the new species against conical spines in others species.

The sanidaster gemmuloscleres found in C. sanidastosclera n. sp. also implies an intermediate stage between those freshwater sponges with acanthostrongyle and birotule gemmuloscleres.In the sanidasters the spines are reaching the tips of the spicules and forming a birotule-like sanidaster. This finding again reinforces the idea of Penney & Racek (1968) that the segregation of Spongillidae into two groups based on the morphology of gemmuloscleres as proposed by Vejdovsky (1887) is not longer justified. In Radiospongilla acanthostrongyles and birotules are present in different species, whereas in Corvoheteromeyenia sanidastosclera n. sp. the pattern is present within a single species.

Figures

FIG. 2.— Corvoheteromeyenia Ezcurra de Drago,1979,Paulo Afonso municipality,Bahia State,in the shores of São Francisco River,Brazil:A, B, Corvoheteromeyenia heterosclera (Ezcurra de Drago, 1974), in situ; C, Corvoheteromeyenia heterosclera, in situ, on the left side and Corvoheteromeyenia sanidastosclera n. sp., in situ, on the right side; D, Corvoheteromeyenia sanidastosclera n. sp., in situ. Scale bars: 1 cm.

FIG. 5. — Spicules of Corvoheteromeyenia sanidastosclera n. sp. (UFPEPOR1105), spicular components: A, B, megasclere acanthoxea;C, D, microscleres pseu- dobirotules; E, gemmuloscleres sanidaster; F, gemmule; G, foramen of gemmule; H, gemmules with gemmuloscleres inserted radially. Scale bars: A, H, 100 μm; B-D, 10 μm; E, 30 μm; F, 300 μm; G, 50 μm.