Corvoheteromeyenia heterosclera

Nicacio, Gilberto & Pinheiro, Ulisses, 2015, Biodiversity of freshwater sponges (Porifera: Spongillina) from northeast Brazil: new species and notes on systematics, Zootaxa 3981 (2), pp. 220-240 : 225-227

Corvoheteromeyenia heterosclera (Ezcurra de Drago, 1974)

( Figure 5 )

Corvomeyenia heterosclera Ezcurra de Drago, 1974a: 233; Volkmer-Ribeiro 1981: 89.

Corvoheteromeyenia heterosclera, Volkmer-Ribeiro et al. 1998b: 273 , Volkmer-Ribeiro et al. 1999: 644, Volkmer-Ribeiro & Pauls 2000: 14, Ezcurra de Drago 2004: 20, Manconi & Pronzato 2005: 3237, Volkmer-Ribeiro 2007: 119, Volkmer- Ribeiro & Machado 2007: 158, Amaral et al. 2008: 158, Volkmer-Ribeiro & Machado 2008: 239, Volkmer-Ribeiro & Machado 2009: 338.

For other synonyms see Muricy et al. (2011).

Material studied. UFPEPOR1095, 1096 (in part), Capibaribe River, Jaboatão dos Guararapes, Pernambuco, Brazil, 08°02'47,4''S 34°59'41,9''W, coll. G. Nicacio, 24.x.2009. UFPEPOR975, 981, 982, 983, coll. G. Nicacio, 12.xii.2009, UFPEPOR1347, 1349, coll. U. Pinheiro, 23.v.2012, Pirangi River, Jaqueira, Pernambuco, Brazil, 08°44'53,0"S 35°48'51,1"W. UFPEPOR1144, 1145, 1146, 1147, 1148, 1149, Sirinhaém River, Cortês, Pernambuco, Brazil, 08º30'6,5"S 35º31'28,6"W, coll. G. Nicacio, 06.ii.2011. UFPEPOR1174, 1175, 1176, 1177, 1178, Pajeú River, Serra Talhada, Pernambuco, Brazil, 07º58'7''S 38º19'23,6''W, coll. G. Nicacio, 17.vii.2011. UFPEPOR1299, Pajeú River, Floresta, Pernambuco, Brazil, 08º36'23,2''S 38º34'21,7''W, coll. L.R.C. Lima, 10.x.2011.

General morphology. Encrusting sponges, circular, thin or thick. Ranging from 5 to 50cm in diameter and 0.5 to 3cm of thickness. The colour is green when found in areas exposed to sunlight or white in sciaphilous habitatd. Surface hispid. Megascleres oxea (204-364/9-18µm), straight or slightly bent, sparsely microspined at middle of shaft ( Fig. 5 a). Microscleres pseudo-birotules of two types, very variable in shape and shaft size: one tiny slender (sometimes erroneously reported as “isochela”) with straight, smooth or spiny shaft (12–42µm), rotules deeply cut with irregular number of minute hooks, curved towards the shaft ( Fig. 5 b,c). The other are spiny oxeas (33–108/ 3µm), with larger spines at middle of shaft, often at edge some spines may present as hooks forming microrotules ( Fig. 5 d). Gemmuloscleres predominantly straight birotules (52–78/3–6µm), with remarkable variation in length, width, rotules almost flat (18–24µm), borders regularly cut in small to hook-like teeth, shaft with abundant, large, sharp, regular, straight spines ( Fig. 5 e). In addition, rare small birotules (57–69/3µm) with slender smooth shaft with uncut rotules (9–18µm) ( Fig. 5 e-l). Gemmules are hemispherical (460–520µm), often abundant at basal portion and also scattered in the sponge body ( Fig. 5 m). Gemmular theca with well-developed pneumatic layer of spongin fibres (without chambers) and gemmuloscleres radially embedded ( Fig. 5 n).

Distribution and ecological notes. Brazil ( Muricy et al. 2011); Argentina (Ezcurra de Drago, 1974a, 2004), Costa Rica ( Volkmer-Ribeiro & Machado, 2009), Curaçao, Venezuela ( Volkmer-Ribeiro & Pauls, 2000; Debrot & Van Soest, 2001; Manconi & Pronzato, 2005; Volkmer-Ribeiro & Machado, 2007). Specimens were found on rocky substrates in shallow running waters. The green colour is due to symbiosis with green algae, which is common in freshwater sponges when they grow exposed to sunlight ( Wilkinson 1980). The thick specimens were found only in sites polluted by waste from sugar cane field in the Sirinhaém River. This may be because that is a favourable habitat for the growth of these sponges since it has a suitable source of organic matter and bacteria ( Reiswig 1975). Other specimens were found in wadis in the semi-arid Caatinga region, in which a large number of gemmules were often found and even isolated massive groups of gemmules were collected from the riverbed.

Remarks. Corvoheteromeyenia is a genus restricted to the Neotropical region with records from Central to South America, where two species, C. australis (Bonetto & Ezcurra de Drago, 1966) and C. heterosclera are so far known from Argentina, Brazil, Costa Rica and Venezuela. Some issues still concern about the taxonomy of these species. Corvoheteromeyenia was erected to assign these species, originally ascribed as members of Corvomeyenia . Microscleres pseudo-birotules and gemmuloscleres birotules present in Corvomeyenia australis and Corvomeyenia heterosclera were the main subsequently revised morphotraits and these species were transferred to Corvoheteromeyenia (Ezcurra de Drago 1979).

According to the original description, C. australis was described from small specimens, but these were not housed in any collection and are unavailable for study and comparison (personal communication, Inés Ezcurra de Drago). Furthermore, the author emended the original description later when new features about microscleres length and shape were added to the description of species. When the author compared specimens of the original description to those in the emended description, remarkable differences were noted in gemmuloscleres—such as the number of shaft spines and variability in the shape of rotules. Thus, the authors established that it could not be stated that there were two types of gemmuloscleres according to the species’ original description, and that a new species should be erected (Ezcurra de Drago, 1974a). However, in spite of these issues about the description of C. australis, Ezcurra de Drago (1974a) described C. heterosclera as a new species for the genus based on its gemmuloscleres, from material collected on northeast Brazil (Holotype MNHNM 22) and Corrientes, Argentina (Paratypes in MACN and INALI), but these specimens are still not available for study and revision.

In this study, we compared a large number of specimens from material studied with the previous descriptions of both species of this genus (Bonetto & Ezcurra de Drago 1966, Ezcurra de Drago 1974a, Tavares et al. 2003, Debrot & van Soest 2001, Volkmer-Ribeiro & Machado 2007, 2009, Machado et al. 2012). On this basis we concluded that there are some problems in the taxonomy of this species, where we could not see a clear differentiation between C. australis and C. heterosclera based on gemmuloscleres as proposed in the original description. Considerable variation in size and shape of the gemmuloscleres were observed in all specimens. These issues should be resolved with additional records and redescriptions of these species from the Neotropical Region. A detailed study of material from original localities of these species is required, thus additional efforts are needed to elucidate this problem.

Figures

FIGURE 5. Corvoheteromeyenia heterosclera: (a) megasclere; (b) microsclere pseudobirotules small; (c-d) microsclere pseudobirotule large; (e-l) gemmuloscleres; (m, n) gemmules. Scale bars: a— 50 µm; b— 5 µm; c, d— 10 µm; (e – l) — 20 µm; m, n— 100 µm.