Marijn Roosen

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Verified

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• Bachelor of Science
• Collection assistent at Naturalis Biodiversity Center

With this study, we continue the revision of the genera of Scolodontidae (Gastropoda: Styl­ommato­phora), focusing on the taxa with tightly coiled, multiwhorled shells that often bear apertural and/or internal barriers. We analysed type material from all type species and studied some misclassified Charopidae and Streptaxidae. We provide redescripti...

Currently, there are many issues with genus-level taxa within the Scolodontidae. This is the second paper in a series which aims to resolve the most prominent issues. Here, we highlight some of the more poorly known, smaller, discoid genera: Guestieria Crosse, 1872 and Xenodiscula Pilsbry, 1919. Guestieria is characterized by its small to medium-si...

While elucidating the evolutionary trajectory of green anacondas, we previously documented the existence of two distinct species, Eunectes akayima sp. nov. and Eunectes murinus (Linnaeus, 1758), that separated approximately 10 million years ago. Our research integrates a novel molecular clock approach, focuses on tectonic plate movements with fossi...

A broken shell of a ?Radiodiscus species is described from the Un poco del Chocó nature reserve (Pichincha province, Ecuador). This is the first time a species of Charopidae from Ecuador is described and imaged, but as small taxa have not received a lot of attention in previous studies more species are expected to be found in the country.

Currently there are several problems with the genus-level taxa within the Scolodontidae. Multiple type-species designations have been proposed for some genera, type species are poorly described, and in some cases no clear decisions have been made in cases of homonymy or synonymy. This has resulted in wrongly identified species and genera within thi...

Toroidia carolinensis sp. nov. is describedbased on material collected by the RV ‘Pelagia’ near the coast of North Carolina (USA), deposited in the Natural History Museum Rotterdam. This new record greatly extends the known distribution of Toroidia Hoffman &Freiwald, 2018 westward, as species have so far only been known from continental shelves in...

Description of a new species of the genus Drymaeus (Albers, 1850) from Northern Peru and new data on Drymaeus valentini (Gastropoda: Bulimulidae) Drymaeus ommatidia sp. nov. (family Bulimulidae) is described from northern Peru (Department of Amazonas) and its relations with known species are briefly discussed. In addition, new occurrences of Drymae...

Helix excisa L. Pfeiffer, 1855 is moved to the genus Hirtudiscus Hylton Scott, 1973, based on conchological characteristics. This decision has implications on scolodontid taxonomy, as several major papers used Helix excisa to redefine Drepanostomella Bourguignat, 1890.

Xenodiscula Pilsbry, 1919 is a poorly known genus of micro gastropods with a seemingly wide distribution in Middle and South America. The main purpose of this paper is to describe a new species from the Tumbes-Chocó-Magdalena hotspot, Xenodiscula yumbo sp. nov., as well as providing a redescription and updated distribution data for all known taxa....

This short paper reports on the discovery of two lithic artefacts and some faunal remains of mammoth and woolly rhinoceros from the Argex-quarry at Kruibeke (East Flanders). The finds were retrieved from a gravel layer at the contact between the Boom clay and the Pleistocene coversand at the base of the Flemish Valley. The freshness of the largest...

In 2019, an extensive survey of the terrestrial gastropods from the Un poco del Chocó Nature Reserve (UPDC) was conducted, in order to assess the gastropod biodiversity and collect some preliminary data on their ecology. During this study, many new and poorly known taxa were found. This paper is the first dedicated to describing the gastropods from...

A new species of Trigonostoma (Gastropoda; Cancellariidae) from the Middle Miocene North Sea Basin is described, Trigonostoma ariejansseni nov. sp., and compared to similar congeners.

A revision of all known Bourciera Pfeiffer, 1852 species is provided and six species are described as new to science: Bourciera amazonensis sp. nov., Bourciera curvidigitata sp. nov., Bourciera distincta sp. nov., Bourciera imbaburensis sp. nov., Bourciera intermedia sp. nov. and Bourciera ovata sp. nov. Based on new material and observations the s...

This comprehensive checklist of non-marine molluscs from the mainland of Ecuador pre- sents data on 331 species (of which 5 are considered as nomen dubium), compiled from the literature, a subset of museum databases, and some verified observations from the internet. For all taxa the original reference is given and photographs of type specimens are...