Rodrigo B. Salvador

Water Vapor Conductance of the Lower Cretaceous Dinosaurian Eggs from Sanagasta, La Rioja, Argentina: Paleobiological and Paleoecological Implications for South American Faveoloolithid and Megaloolithid Eggs

ABSTRACT The water vapor conductance (GH2O) of the neosauropod eggs from the Lower Cretaceous Sanagasta nesting site in La Rioja Province, Argentina, was examined and compared with other Cretaceous Argentinean oological material. The 2900 mgH2O/day·Torr GH2O of the Sanagasta eggshells confirms an extremely moist nesting environment and supports field observations of dug-out nests in a geothermal setting. The observed thinning of the outer eggshell surface during incubation increases gas conductance and concomitantly decreases eggshell mechanical resistance during the late ontogenetic stages, thus facilitating embryonic development and hatching. The Sanagasta and Entre Ríos Province faveoloolithid eggs display the highest and comparable GH2O values and share several morphological and diagenetic characters, indicating comparable nesting strategy in geothermal settings. However, the faveoloolithid Yaminué and La Pampa Province specimens cluster together with lower GH2O values closer to the megaloolithid eggs. The GH2O of the megaloolithid egg Megaloolithus patagonicus was reconsidered and new results are now congruent with other reported megaloolithid GH2O values. Additionally, we hypothesize that Y-shaped pore canals of M. patagonicus, which upper sections reach only the top third or half eggshell thickness and, a wider section in the middle would not compromise the overall egg mechanical resistance like vertical pores connecting directly the outer to the inner eggshell surfaces. Such pore spatial arrangement and geometry would enhance, as the eggshell thins during incubation, a greater GH2O, GO2 and GCO2 and facilitate embryonic development in high moisture nesting contents. Overall, data suggests that neosauropod nesting and brooding behaviors were dependent on elevated moisture nesting environments.

A Large Accumulation of Avian Eggs from the Late Cretaceous of Patagonia (Argentina) Reveals a Novel Nesting Strategy in Mesozoic Birds

We report the first evidence for a nesting colony of Mesozoic birds on Gondwana: a fossil accumulation in Late Cretaceous rocks mapped and collected from within the campus of the National University of Comahue, Neuquén City, Patagonia (Argentina). Here, Cretaceous ornithothoracine birds, almost certainly Enanthiornithes, nested in an arid, shallow basinal environment among sand dunes close to an ephemeral water-course. We mapped and collected 65 complete, near-complete, and broken eggs across an area of more than 55 m2. These eggs were laid either singly, or occasionally in pairs, onto a sandy substrate. All eggs were found apparently in, or close to, their original nest site; they all occur within the same bedding plane and may represent the product of a single nesting season or a short series of nesting attempts. Although there is no evidence for nesting structures, all but one of the Comahue eggs were half-buried upright in the sand with their pointed end downwards, a position that would have exposed the pole containing the air cell and precluded egg turning. This egg position is not seen in living birds, with the exception of the basal galliform megapodes who place their eggs within mounds of vegetation or burrows. This accumulation reveals a novel nesting behaviour in Mesozoic Aves that was perhaps shared with the non-avian and phylogenetically more basal troodontid theropods.

Early Miocene continental gastropods from new localities of the Molasse Basin in southern Germany

Here, we present the continental aquatic and terrestrial gastropods found in samples of 11 new boreholes in the Molasse Basin, southern Germany. The samples come from the Lower Freshwater Molasse (USM), the Upper Brackish Molasse (OBM; Grimmelfingen and Kirchberg Formations) and the Upper Freshwater Molasse (OSM). The studied segments of these lithostratigraphical units represent the beginning of the lower Miocene (USM), and the uppermost lower Miocene (OBM, OSM). Twenty-four species of terrestrial and freshwater gastropods are reported here, belonging to the families Neritidae, Melanopsidae, Pachychilidae, Bithyniidae, Hydrobiidae, Truncatellidae(?), Viviparidae, Valvatidae(?), Lymnaeidae, Planorbidae, Carychiidae, Zonitidae, Helicidae, Hygromiidae and Discidae(?). We provide remarks on the taxonomy of some of the studied species, including a revision of Theodoxus cyrtocelis, T. obstusangula and T. sparsus (the latter can be considered a synonym of T. cyrtocelis). Finally, we present a paleoecological interpretation for the USM, OBM and OSM based on the gastropod fauna.KurzfassungBasierend auf den Proben von 11 in den letzten Jahren durchgeführten Bohrungen im süddeutschen Molassebecken wird die kontinentale aquatische und terrestrische Gastropodenfauna neu bearbeitet. Das Material stammt aus Proben der Unteren Süßwassermolasse (USM), der Oberen Brackwassermolasse (OBM; Grimmelfingen und Kirchberg Formationen) und der Oberen Süßwassermolasse (OSM). Die hier bearbeiteten Abschnitte dieser lithostratigraphischen Einheiten sind in das unterste Unter-Miozän (USM) bzw. in das oberste Unter-Miozän (OBM, OSM) einzustufen. Insgesamt werden 24 Arten kontinentaler Gastropoden aus den Familien Neritidae, Melanopsidae, Pachychilidae, Bithyniidae, Hydrobiidae, Truncatellidae(?), Viviparidae, Valvatidae(?), Lymnaeidae, Planorbidae, Carychiidae, Zonitidae, Helicidae, Hygromiidae und Discidae(?) beschrieben. Die Taxonomie einiger dieser Arten wird kritisch beleuchtet und die Arten der Gattung Theodoxus (T. cyrtocelis, T. obstusangula, T. sparsus) warden revidiert, T. sparsus wird als Synonym von T. cyrtocelis interpretiert. Darüber hinaus wird auf der Grundlage der Gastropodenfauna eine paläoökologische Interpretation für die USM, OBM und OSM gegeben.

Taxonomic revision of the orthalicid land snails (Pulmonata: Stylommatophora) from Trindade Island, Brazil

Land snails (stylommatophoran pulmonates, shells only) were collected on Trindade Island, ∼1140 km off Vitória, Brazil, by the Marion Dufresnei Expedition (MD-55) and more recently by our team. Trindades endemic snails are Bulimulus brunoi and Naesiotus arnaldoi (Orthalicidae), and Oxyloma beckeri and Succinea lopesi (Succineidae). As some non-native species have also been found, a taxonomic revision of the native fauna was needed. Here, the revision is focused on orthalicids, presenting updated descriptions and diagnosis. Moreover, the supposed native orthalicid Bulimulus trindadensis is deemed here to be a Subulinidae, and the new genus Vegrandinia is erected to accommodate it. Trindades insular environment is delicate and very susceptible to invasive species. No living specimens of these taxa, native or non-native, have been collected since before the MD-55 Expedition. However, it is still premature to assume that the introduced species have failed to establish themselves or that the native species are now extinct. http://www.zoobank.org/urn:lsid:zoobank.org:pub:6B1D6F63-EFB0-400A-8C0C-B508EAEB0A4B

Taxonomical study on a sample of land snails from Nanuque (Minas Gerais, Brazil), with descriptions of three new species

Abstract A sample of land snails was recently collected in a fragment of Atlantic rainforest, in the vicinities of the city of Nanuque (north of Minas Gerais state, Brazil), totaling 15 species. The following new species are herein described: Leiostracus carnavalescus n. sp. and Rhinus botocudus n. sp. (Bulimulidae), and Obeliscus boitata n. sp. (Subulinidae), the first two accompanied by anatomical descriptions. Moreover, the geographical ranges of some species are extended to Minas Gerais: Auris bilabiata, Bahiensis cf. bahiensis, Cyclopomops moricandi, Dysopeas muibum, Helicina boettgeri, Helicina variabilis, Prohappia besckei, and Rectartemon piquetensis. The discovery of new species in such a small forest fragment is a clear reminder of how little the Brazilian terrestrial snail fauna is known. It also points to the fact that these few remaining forest fragments may house many new and possibly endemic species and should, therefore, be properly preserved.

Annotated type catalogue of the continental fossil gastropods in the Staatliches Museum für Naturkunde Stuttgart, Germany

Abstract The type specimens of fossil land and freshwater gastropods deposited in the Staatliches Museum für Naturkunde Stuttgart (SMNS), Germany, are listed and illustrated herein, comprising circa 180 nominal species-group taxa from Cenozoic fossil sites, mainly in the Baden-Württemberg and Bayern states in southern Germany. The list is arranged in alphabetical order of the specific epithets, with information on the original description, taxonomical status, type locality, record number in the collection and comments. A systematically arranged list of the taxa is also given, as well as a list arranged by authorship of the species-group names. At least one type specimen (holotype, lectotype, syntype or neotype) of each nominal species/subspecies is figured here, and further specimens were figured when they added information. In some cases lectotypes are designated herein.

New species of Cyclodontina from Bahia, Brazil (Gastropoda, Pulmonata, Odontostomidae)

A new species of pulmonate snail was recently collected in a small forest fragment in the city of Bom Jesus da Lapa, Bahia state, Brazil. Bahia is known for a high diversity of land snails and Bom Jesus da Lapa is an interesting locality, since it is close to the interface between two major Brazilian biomes: Cerrado and Caatinga. The new species is described as Cyclodontina tapuia sp. nov. and can be easily identified by its brown shell, conical spire, convex whorls, a sculpture comprised of strong ribs, and an aperture with four barriers: a median parietal tooth, a median palatal tooth, a median basal tooth and a strong columellar lamella. This discovery is also a reminder of how little the Brazilian continental molluscan fauna is known and of the urgency in studying and preserving the rich (though usually overlooked) fauna of the Caatinga.

A new species of Kora from Bahia, Brazil (Gastropoda: Pulmonata: Orthalicoidea), with an emended diagnosis of the genus

Abstract A new species of land snail was recently found in the municipalities of Carinhanha, Serra do Ramalho and Coribe, western Bahia state, Brazil. It is described herein as Kora rupestris n. sp. and can be easily recognized from its congeners by its usually narrower shell and aperture, and especially by its protoconch sculpture pattern. In light of this new discovery, new emended diagnosis and description are provided for the genus Kora, and two taxa previously described under this genus are excluded, being transferred to the genus Drymaeus [D. iracema (Simone, 2015) n. comb. and D. terreus (Simone, 2015) n. comb.]. The region where the new species was found consists of a contact zone of the Caatinga and Cerrado biomes. Such regions are proving to be quite diverse and a more thorough knowledge of their fauna is of utmost importance for future conservation efforts.

The fossil land and freshwater snails of Gündlkofen (Middle Miocene, Germany)

The molluscan fauna from the Middle Miocene (MN 5-6) fossil site of Gündlkofen in southern Germany was first reported by Gall (1980: Mitt. Bayer. Staatssaml. Paläont. hist. Geol., 20, 51-77). He listed 34 continental gastropod species, which were neither figured nor properly described in many cases. Here a revision of his identifications is presented, with a full description of the material and illustration of the best preserved specimens. Following this revision, 20 species are listed for Gündlkofen. Unfortunately, part of the original material was missing and the record of a few species could not be confirmed. The depositional environment seems to have been a temporary water body, like an oxbow lake, surrounded by a humid and warm forest and scrubland.

Miocene continental gastropods from Dischingen, Germany

Abstract Here is given an account, based on museum collections, of the fossil land and freshwater gastropods from Dischingen (Baden-Württemberg state, SW Germany). The fossiliferous outcrops belong to the Silvana Beds unit of the Upper Freshwater Molasse group, of late Early to early Middle Miocene age (Neogene European Land Mammal Zone MN 5). In total, 35 gastropod species were found (seven freshwater and 28 terrestrial), mainly belonging to Pulmonata, but also with representatives of Neritimorpha and Caenogastropoda. Seven species are reported here for the first time from Dischingen: Palaina diezi, Radix socialis, Granaria sp., Serrulina? sp., Discus pleuradrus, Punctum pumilio, and Oxyloma minima.