A morphological guide of neotropical freshwater sponge spicules for paleolimnological studies

Freshwater sponges (Porifera: Spongillida) are sessile invertebrates with skeletons composed of siliceous elements termed spicules. Sponge spicules (megascleres, microscleres, and gemmuloscleres) are characterized by widely varying sizes and shapes. These spicules are well-preserved in lacustrine, wetland, and riverine sediments and hold significant ecological and limnological information that can be applied as diagnostic tools in reconstructions of Quaternary environments. However, problems with taxonomy and the absence of systematic guidelines and standards of identification represent major challenges to utilizing freshwater sponges as a paleo-proxy. Here, we present a well-illustrated extraction protocol and morphological guide to the Neotropical freshwater sponge fauna. This guide is intended to introduce researchers and students to the study of freshwater sponges and their use as a diagnostic tool in paleoecology and paleolimnology

A new species of Anheteromeyenia (Porifera, Demospongiae) with an emended diagnosis of the genus

Calheira, Ludimila, Pinheiro, Ulisses (2018): A new species of Anheteromeyenia (Porifera, Demospongiae) with an emended diagnosis of the genus. Zootaxa 4378 (1): 129-136, DOI: https://doi.org/10.11646/zootaxa.4378.1.

Des sanidasters chez les éponges d’eau douce : une spicule inattendue chez le genre birotulées <i>Corvoheteromeyenia</i> Ezcurra de Drago, 1979

Corvoheteromeyenia Ezcurra de Drago, 1979 est trouvé exclusivement dans la région néotropicale, où elle est connue par deux espèces: C. australis (Bonetto &amp; Ezcurra de Drago, 1966) et C. heterosclera (Ezcurra de Drago, 1974). Le genre est caractérisé par la présence de gemmuloscleres birotulées insérées radialement dans la gemmule ; de mégasclères uniquement composées d’oxes, occasionnellement couvertes par des microépines ; et des microsclères pseudobirotulées présentes en deux séries distinctes. Douze spécimens, appartenant au genre Corvoheteromeyenia, ont été échantillonnés dans le bassin du São Francisco (Bahia, Brésil). À partir de ce matériel, nous signalons l’espèce C. heteroscleres pour le bassin du São Francisco. De plus, nous décrivons une nouvelle espèce de Corvoheteromeyenia qui diffère des autres espèces du genre par la présence de gemmulosclères sanidasters. Ces sanidasters ont une morphologie intermédiaire entre les formes birotulées et les formes de bâtonnet (acanthostrongyles). La présence de gemmulosclère sanidasters pourrait être interprêtée comme une malformation due aux conditions environnementales, puisque des malformations des gemmulosclères ont déjà été observées en conditions expérimentales, quand certaines éponges d’eau douce étaient exposées à des métaux lourds. Cependant, seulement 50 % des gemmulosclères étaient alors malformées, alors que chez C. sanidastosclera n. sp. 100 % des gemmulosclères sont sanidasters. Nous ne croyons donc pas que la morphologie de ces spicules soit un résultat d’une exposition aux composés chimiques dans l’environnent. Nos résultats renforcent l’hypothèse de Penney &amp; Racek (1968) selon laquelle la séparation des Spongillidae Gray, 1867 en deux groupes d’après la forme de leur gemmulosclère comme proposée par Vejdovsky (1887) n’est plus justifiée.Corvoheteromeyenia Ezcurra de Drago, 1979 is exclusively known from Neotropical Region with two species recorded: C. australis (Bonetto &amp; Ezcurra de Drago, 1966) and C. heterosclera (Ezcurra de Drago, 1974). The genus is characterized by the presence of birotuled gemmuloscleres inserted radially embedded in the gemmule, by megascleres which are exclusively oxeas, occasionally sparsely microspined and pseudobirotuled microscleres present in two distinct series. A total of twelve specimens were collected in São Francisco Basin (Bahia State, Brazil) and identified as belonging to C­orvoheteromeyenia. Based on this material, we record C. heterosclera for São Francisco Basin. Additionally, we describe a new species of Corvoheteromeyenia that differs from other species of genus by having gemmulosclere sanidaster. Sanidaster display an intermediate morphology between the birotule and rodlike (acanthostrongyle) spicular type. The gemmulosclere sanidaster found here could be interpreted as malformations due to environmental conditions, since malformations in gemmuloscleres had previously been observed in experimental conditions in some freshwater sponges exposed to heavy metal. However, in these conditions only 50% of gemmoscleres were malformed, and in C. sanidastosclera n. sp., 100% of gemmoscleres were sanidasters. Thus we do not believe that this morphology of spicules was the result of exposure to chemical compounds in the environment. This result reinforces the idea of Penney &amp; Racek (1968) that the segregation of Spongillidae Gray, 1867 into two groups based on the form of gemmoscleres as proposed by Vejdovsky (1887) is no longer justified.</p

A new species of freshwater sponge, Heteromeyenia barlettai sp. nov. from an aquarium in São Paulo, Brazil (Spongillida: Spongillidae)

Pinheiro, Ulisses, Calheira, Ludimila, Hajdu, Eduardo (2015): A new species of freshwater sponge, Heteromeyenia barlettai sp. nov. from an aquarium in São Paulo, Brazil (Spongillida: Spongillidae). Zootaxa 4034 (2): 351-363, DOI: http://dx.doi.org/10.11646/zootaxa.4034.2.

Table_1_A morphological guide of neotropical freshwater sponge spicules for paleolimnological studies.DOCX

Freshwater sponges (Porifera: Spongillida) are sessile invertebrates with skeletons composed of siliceous elements termed spicules. Sponge spicules (megascleres, microscleres, and gemmuloscleres) are characterized by widely varying sizes and shapes. These spicules are well-preserved in lacustrine, wetland, and riverine sediments and hold significant ecological and limnological information that can be applied as diagnostic tools in reconstructions of Quaternary environments. However, problems with taxonomy and the absence of systematic guidelines and standards of identification represent major challenges to utilizing freshwater sponges as a paleo-proxy. Here, we present a well-illustrated extraction protocol and morphological guide to the Neotropical freshwater sponge fauna. This guide is intended to introduce researchers and students to the study of freshwater sponges and their use as a diagnostic tool in paleoecology and paleolimnology.</p