Duplexium jatobensis & Anhapoa munizi: Freshwater Mussels from the Early Cretaceous of northeastern Brazil.

Freshwater Mussels, Unionida, are the only order of Bivalves found exclusively in freshwater. There are about 900 species today, found on every continent, with some species considered economically significant, due to their use as food, their ability to produce pearls, their ability to modify environments, or their impact upon Fish stocks. Unionids have a unique life cycle among Bivalves, with a larval stage which lives commensually or parasitically on the skin, fins, or gills of a Fish host.

In a paper published in the Journal of South American Earth Sciences on 20 May 2025, Débora Eliza Baumann of the Laboratório de Paleontologia de Macroinvertebrados at São Paulo State University, Luiz Ricardo Simone of the Laboratório de Malacologia at the Museu de Zoologia of the Universidade de São Paulo, Rafael Costa da Silva of the Museu de Ciéncias da Terra of the Serviço Geológico do Brasil, and Renato Pirani Ghilardi, also of the Laboratório de Paleontologia de Macroinvertebrados at São Paulo State University, describe two new species of Unionid Freshwater Mussels from the Early Cretaceous Salvador Formation of Pernambuco State, Brazil.

The Salvador Formation outcrops in the Jatobá Basin of Pernambuco State, and records a fan delta laid down within a palaeolake in the Late Berriasian age (roughly between 140 and 137 million years ago). Both new species are described from specimens collected at a site designated BL-42 within the city of Floresta, and held within the collection of the Museu de Ciéncias da Terra of the Serviço Geológico do Brasil.

Location of Jatoba Basin (08◦30′ to 9◦06′ S; 37◦06′ to 38◦30′ W) in Northeast Brazil, location where the fossils are collected (8◦41′48.60″S 38◦16′34.30″W) and stratigraphy of the Jatoba Basin. Baumann et al. (2025).

The first new species is named Duplexium jatobensis, where 'Duplexium' refers to the fact that it has two types of teeth on its hinge, and 'jatobensis' means 'from Jatobá' in reference to the Jatobá Basin where it was discovered. The species is described from four specimens, which are between 47 and 50 mm in length, 18-19 mm in width, and 6-8 mm in thickness, with three teeth on the hinge, the central one of which is distinctly larger than the other two.

Holotype, MCT.I.7202. Duplexium jatobensis; Salvador Formation (Berriasian), general morphology and muscle scars. Abbreviations: aa, anterior adductor; pa, posterior adductor; pl, pallial line; ht, heterodont teeth; tt, taxodont teeth; pp, pedal protractor; apr, anterior pedal retractor; pe, pedal elevator; S1, posterior pedal retractor? S2, posterior adductor? or S1 + S2, slow and fast components of the posterior adductor? Scale bar is 10 mm. Baumann et al. (2025).

The second new species is named Anhapoa munizzi, where 'Anhapoa' derives from 'Anhapoā', which means 'canine tooth' in the Tupi-Guarani indigenous language of Brazil, in reference to a well-pronounced cardinal tooth on the hinge of the right valve of the shell. Anhapoa munizzi is described from five specimens, which range from 43 to 52 mm in length, 23 to 27 mm in width, and from 8 to 14 mm in thickness. The hinge of the right valve has a large cardinal tooth between two pits, and small lateral teeth.

Holotype, MCT.I.7147, Anhapoa munizi, Salvador Formation (Berriasian), general morphology and muscle scars. Abbreviations: aa, anterior adductor; pa, posterior adductor; pl, pallial line; ht, heterodont teeth; tt, taxodont teeth; pp, pedal protractor; apr, anterior pedal retractor; pe, pedal elevator, S1, posterior pedal retractor? S2, posterior adductor? or S1 + S2, slow and fast components of the posterior adductor? Scale bar is 10 mm. Baumann et al. (2025).

Both Duplexium jatobensis and Anhapoa munizi lack any form of ornamentation, have smooth beak, lack a prodissoconch, have a heterodont hinge and an additional taxodont hinge, have an elevator muscle scar, and lack a pallial sinus, all traits consistent with assignment to the Family Iridinidae within the Superfamily Etherioidea, one of the two major subdivisions of the Unionida.

The oldest members of the Family Iridinidae described to date come from the Middle Cretaceous of Africa, with some possible Iridinid fossils from the End Cretaceous of South America. Modern Iridinids are restricted to Africa, leading malacologists toconclude that the genus originated there, after the continents of Africa and South America split apart, between 140 and 120 million years ago. The Salvador Formation of the Jatobá Basin, however, was laid down during the earliest part of this rifting process, when Africa and South America were still joined, raising the possibility that the Iridinidae originated in South America, but died out there during the End Cretaceous Extinction.

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Heteromeyenia cristalina & Radiospongilla inesi: Determining the environmental tolerances of the gemmules of two species of Neotropical Freshwater Sponge.

Inland waters are susceptible to extreme environmental conditions including freezing, drying or high salinity. In these environments, it is common to find animals with several adaptive strategies to these variable conditions. Freshwater Sponges, Spongillida, for example, produce resisting bodies known as gemmules, which can survive unfavorable conditions. Gemmules can be found in species belonging to three families currently placed in the order Spongillida. Potamolepidae species deposit gemmules with a simple architecture at the Sponge-substrate interface, whereas gemmules of the Spongillidae and Metaniidae are distributed throughout the Sponge body and have complex gemmule morphologies with a well-developed pneumatic layer, and spiny gemmuloscleres (specialized spicules found only in the gemmules). Completely formed gemmules exhibit low metabolic rates and may become dormant. Most Freshwater Sponges undergo a period of dormancy at some time during the year, typically during periods of environmental stress, until hatching occurs. The dormancy of gemmules is likely to be controlled by interactions between exogenous (e.g., temperature, light, salinity, oxygen tension, and pH) and endogenous factors (e.g. concentrations of calcium, and osmotic pressure). It is likely that that such endogenous processes are involved in the control of life cycle phases, and seasonality and length of phases are subject to exogenous limiting factors, such as ice-up and dry-upfreezing and drying.

In a paper published in the journal Iheringia Série Zoologia on 10 January 2020, Ludimila Calheira, Paulo Santos, and Ulisses Pinheiro of the Departamento de Zoologia at the Universidade Federal de Pernambuco, present the results of a study designed to test the capacity of hatching under differnt conditions of the gemmules from two Neotropical Freshwater Sponges, both belonging to the family Spongillidae; Heteromeyenia cristalina and Radiospongilla inesi.

Stressful conditions can be crucial to the success of gemmules hatching in some species. Prvious studies have shown that exposure of gemmules to low temperatures or drying can stimulate hatching when conditions resume later to an ideal environmental condition, respectively in the cases of Eunapius fragilis and Metania spinata. Gemmules of Ephydatia muelleri, Racekiela ryderii, and Spongilla lacustris, also have been shown to be tolerant of low temperatures. Most studies on the hatchability of gemmules have focused in low temperatures and drying, but studies have also tested Eunapius fragilis for salinity tolerance and the ability to survive seasonal anoxia.

Specimens of Heteromeyenia cristalina and Radiospongilla inesi were collected from Fish farming tanks at the Universidade Federal Rural de Pernambuco, fed with water from the Prata River, in northeast Brazil.

Specimen of Heteromeyenia cristalina, in situ. Scale bar is 1 cm. Calheira et al. (2020).

Sponges were individually packed in a container with water of their own environment and transported to the laboratory. Additionally, the tank water was also collected and stored in a glass container. Other samples of water used in the study were all from northeast Brazil: water from the Pirangi River (chosen due to its high diversity of Sponges, with at least four species recorded), water from Araraquara Pond ('humic water' considered to be rich in organic material), and and mineral water from the Emerald Source mineral spring (due to its purity).

Specimen of Radiospongilla inesi, in situ. Scale bar is 1 cm. Calheira et al. (2020).

In the laboratory, gemmules were removed from Sponges and allocated in 24 well (3 ml) plates, containing a single gemmule each, and cultured at room temperature (approximately 25 °C). Five assays were tested: (A1) Water from the Fish farming tanks where the Sponges were collected; (A2) Pirangi River water; (A3) Araraquara Pond water; (A4) mineral water and (A5) dry. Gemmules in test (A5) were stored in Petri dishes covered with filter paper for 10 days to dry. After this period, gemmules were allocated to plates with water from the Fish farming tanks which the Sponges were collected.

For each assay, three replicates with 30 gemmules were used. The gemmules were observed daily during 30 days under a stereomicroscope to register the number of hatching gemmules and how many gemmules develop into juvenile Sponges.

Gemmules of both Heteromeyenia cristalina and Radiospongilla inesi did not hatch when submitted to humic waters (A3). In the other assays (A1), (A2) and (A4) gemmules of both species hatched, with significant differences among assays, and between species.

Gemmule of Heteromeyenia cristalina submitted to Araraquara Pond water. Scale bar is 100μm. Calhiera et al. (2020).

The water of fish farming tanks (A1) yielded high rates of gemmule hatching, 92% for Heteromeyenia cristalina and 80% for Radiospongilla inesi. Gemmules of the two species had different results when submitted to waters from Pirangi River (A2) and mineral water (A4). Radiospongilla inesi showed higher hatching rates with 79% and 78%, against only 8% and 2% for Heteromeyenia cristalina, respectively.

Gemmule of Radiospongilla inesi submitted to Araraquara Pond water. Scale bar is 100μm. Calhiera et al. (2020).

The two species also responded differently to drying. 92% of Heteromeyenia cristalina gemmules placed in water from the tanks from which they were collected without drying hatched, whereas only 66% if those hatched first did so. With Radiospongilla inesi the reverse occured, with 91% of the dried gemmules hatching, but only 80% of the undried gemmules. 

Gemmules of both species submitted to Araraquara Pond waters did not hatch, probably due to its conductivity, which was three times higher than that of the other waters tested by Calhiera et al. The high conductivity of this environment can be explained by the organic matter enrichment. Until now, only six species from Neotropical Freshwater Sponges have been found in humic waters: Corvomeyenia thumi,  Metania spinata, Tubella variabilis, Dosilia pydanieli, Radiospongilla amazonensis, and Corvomeyenia epilithosa. Except for Corvomeyenia epilithosa, none of these species are restricted to humic waters, and all have a wide distribution, indicating adaptive plasticity and the ability to cope with different kinds of inland waters. 

There were significant differences among the assays and between the species. Radiospongilla inesi presented a high hatching rate and sponge development in all non-humic waters tested, whereas Heteromeyenia cristalina had high hatching rate and Sponge development only im its own collection water. These results for Heteromeyenia cristalina were completely unexpected due to its wide distribution on the Neotropical region. Conversely, Radiospongilla inesi has only been known from its type locality until now. Despite belonging to the same family and sharing a complex gemmular morphology, Heteromeyenia cristalina and Radiospongilla inesi  have different levels of adaptation to different environments due to the distinct hatchability potential of their gemmules.

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Lonchophylla inexpectata: A new species of Nectar-feeding Bat from the Caatinga of Brazil.

Nectar-feeding Bats of the genus Lonchophylla are found tropical South and Central America, where they are important pollinators of some plant groups. There are currently twelve recognized species, with a cluster of smaller species having recently been transferred to another genus, Hsunycteris.

In a paper published in the journal ZooKeys on 22 July 2015, Ricardo Moratelli of the Fiocruz Mata Atlântica of the Fundação Oswaldo Cruz and the Division of Mammals at the National Museum of Natural History and Daniela Dias of the Laboratório de Biologia e Parasitologia de Mamíferos Silvestres Reservatórios at the Instituto Oswaldo Cruz, describe a new species of Nectar-feeding Bats of the genus Lonchophylla, from museum specimens collected in the arid Caatinga habitat (dry shrubland and thorn forest) of northeastern Brazil between 1908 and 1976.

The new species is named Lonchophylla inexpectata, where ‘inexpectata’ means ‘unexpected’. It is based entirely on museum specimens previously ascribed to the species Lonchophylla mordax, a species first described in 1903 from Brazil, and which formerly included populations from as far west as Colombia and Ecuador and as far north as Costa Rica, but which is now regarded as exclusively east-Brazilian in distribution. However, while previous taxonomists have removed distant populations from the species, it is currently considered to inhabit both the wet Atlantic Rainforests and arid Caatinga environment within this region, an improbable juxtaposition of habitats.

Moratelli and Dias examined museum specimens of ‘Lonchophylla mordax’ from both Atlantic Rainforest and Caatinga environments, and found that the Caatinga specimens were persistently paler than the Atlantic Forest specimens, many being described in museum records as ‘faded’. Further investigation revealed that these specimens also had smaller skulls, with narrower, more slender snouts, and slightly different dentition, with a well-developed lingual cusp (cusp on the inner, tongue, side of the tooth) on the fourth premolar, which was absent from the Atlantic Forest specimens.

Dorsal (A) and ventral (B) pelage of Lonchophylla inexpectata. Scale bar is 10 mm. Moratelli & Dias (2015).

Lonchophylla inexpectata has not yet been studied as a separate species in the wild, and its exact distribution is unclear, though museum specimens have been identified that were collected in both Pernambuco and Bahia States. However Moratelli and Dias note that expansion of agriculture in eastern Brazil has led to clearing of many areas of Atlantic Rainforest and its replacement with an artificial environment closer to the arid Caatinga, which may have led to Lonchophylla inexpectata expanding its range.

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