Projects | Luciana Martins

Minding the gap on the taxonomic diversity of Crinoidea (Echinodermata) in Brazil

Wed, 31 Aug 2022 04:02:47 +0000

About 670 living species of crinoids occur worldwide and only 20 species have been discovered in Brazil waters to date. Most of these occurrences were reported by 1800s and 1900s expeditions and crinoid-focused studies undertaken by Brazilian researchers are limited to a few publications1–3, none of which include new species, thorough morphological descriptions, or high-quality imaging. Taxonomic revisions focused on other echinoderm classes in recent years have revealed a hidden diversity of new species, which strongly suggests that the Brazilian crinoid biodiversity is underestimated. Also, several taxonomic problems in this class remain unsolved. This project aims to advance our knowledge of the taxonomic diversity of Crinoidea by reviewing all reported Brazilian species and neglected specimens in museum collections. Equipe: Luciana Martins (coordenadora); Camilla Souto (colaboradora); Túlio Souza (undergraduate student). Grant: LinnéSys Systematics Research Fund

Taxonomic review of the Shallow Water Brazilian holothuroids

Sat, 01 May 2021 04:17:18 +0000

Holothuroidea class is currently represented by six orders: Apodida, Aspidochirotida, Elasipoda, Dactylochirotida, Dendrochirotida and Molpadida, with about 1400 species. In Brazil, 37 species of holoturoids are recognized, 32 of which are shallow waters. The taxonomy of the group is quite complex, especially with regard to comparative studies between genera and species, which are commonly organized into groups of species. Although there are few studies that address the occurrence of species of the Phylum Echinodermata in Brazil, including the registration of new species for science, they do not specifically address taxonomic issues of holoturoids, leaving this Class aside. Thus, this work aims to contribute to the knowledge of the shallow-water Holothuroidea biodiversity in the country, performing the taxonomic study of species of this class, redescribing already known species, whose previous characterization lacks complementation of the external morphological components and internal dermal ossicles, prioritizing the registration of possible new species and new occurrences, in addition to expanding the geographic and/or bathymetric distribution of known species.

Macrostructural anatomy of sea cucumber’s calcareous rings

Sat, 01 Jun 2019 04:02:47 +0000

Despite descending from heavily calcified ancestors, the holothuroid skeleton is fully internal and composed of microscopic ossicles and a ring of plates bound by connective tissue, the calcareous ring. The calcareous ring exhibits a complex and poorly understood morphology; as a result, establishing unambiguous homology statements about its macrostructure has been challenging and phylogenetic studies have had to simplify this important structure. The aim of this project is to investigate the 3D anatomy of the calcareous ring under μCT and the relationship between the calcareous ring and its associated organs.

Understanding the evolutionary history of the cassiduloid echinoids

Sat, 01 Jun 2019 04:02:47 +0000

Cassiduloids are irregular echinoids (like sand dollars and heart urchins) that live mainly in shallow tropical waters. There are only about 35 living cassiduloids, but their fossil record is relatively rich. We try to understanding the cassiduloid anatomy, biodiversity, relationships, and the processes that have affected their evolution since their origin in the Cretaceous

Taxonomic review of _Parathyone_ Deichmann, 1957

Tue, 01 Jan 2019 04:02:47 +0000

The genus Parathyone is composed of two Caribbean species, Parathyone surinamensis and Parathyone suspecta, initially described in the genus Thyone and later transferred to the genus Ocnus. In this context, the Brazilian species Parathyone braziliensis (Verril, 1868) is circumscribed, a species widely distributed throughout the Brazilian coast, but little known taxonomically, so that its taxonomic identity and its generic position need revision. The nominal species Phyllophorus palmae is, according to some authors, a species synonymous with Parathyone surinamensis. However, the occurrence of P. surinamensis in Brazil is uncertain, since it was mentioned only in conference abstracts, with no more detailed systematic background. Parathyone suspecta and P. braziliensis share many morphological similarities, which, due to the precarious morphological characterization of both, makes their distinction very difficult. With this, several authors have questioned the validity of these species.

ProTrindade Marine Invertebrate Project

Tue, 01 May 2018 04:17:18 +0000

The degree of isolation of oceanic islands makes these environments an excellent model for evolutionary studies. Proper knowledge of the species composition of oceanic islands, however, is required to better understand evolutionary processes (e.g. speciation events). A 3-year survey in the shallow waters (up to 30 m) of the Trindade and Martin Vaz oceanic insular complex (ProTrindade), and a literature review on the data published for these islands and for Fernando de Noronha and Sa ̃o Pedro and São Paulo oceanic archipelagos have been conducted to document the biodiversity of echinoids and holothuroids from these isolated Brazilian oceanic islands. Sixteen species were collected and characterized morphologically, including two first records for the South Atlantic and one for Brazil. Comparison with conspecific specimens from the Brazilian coast and congeners was also done. Species richness increased from six to 18; the richness in Trindade Island being the highest among the South Atlantic oceanic islands. However, these islands remain undersampled beyond 30-m depth. Endemism was very low, suggesting the potential role of oceanic currents and seamounts as stepping-stones in transoceanic dispersal of species to remote islands. The Brazilian oceanic islands are impoverished oceanic outposts of the Brazilian Province; nevertheless, endemic species and intraspecific morphological variations compared with the mainland suggest they may also be regions of speciation. Documenting their biodiversity is critical for effective management and conservation of their marine ecosystems.

Morphological phylogeny of the families Phyllophoridae and Sclerodactylidae

Sat, 01 Jun 2013 04:02:47 +0000

Currently, the order Dendrochirotida comprises about 800 species, half of these being within the families Sclerodactylidae and Phyllophoridae. Regardless, most information about these families is from old morphological revisions (Phyllophoridae in 1954 and Sclerodactylidae not reviewed). This study appears as the first formal test of the monophyly of the families Sclerodactylidae and Phylllophoridae and their respective subfamilies. The present project will constitute a detailed morphological study of the structures that compose the Holothuroidea endoskeleton which are the dermal ossicles and calcareous ring to achieve through a cladistic analysis the following objectives: (i) to test the monophyly of Phyllophoridae; (ii) to test the monophyly of Sclerodactylidae; (iii) to test the monophyly of the Phyllophoridae subfamilies and (iv) to test the monophyly of the subfamilies of Sclerodactylidae.

Discovering the fossil record of Holothuroidea (Echinodermata) from Brazil

Mon, 01 Jan 0001 00:00:00 +0000

The phylum Echinodermata (sea urchins, sea stars, sea cucumbers) has been known for puzzling zoologists for centuries because of its diverse and unusual body plan, which lacks eyes, limbs, and other common metazoan features. The reduced skeletonization provided numerous ecological opportunities to holothuroids and they often are the most abundant echinoderms in various ecosystems. With over 1,700 living species distributed worldwide, holothuroids can be found from the littoral zone to the deep sea. Although some species live epifaunally, most species burrow in soft substrates. This strategy, only possible because of their soft body, allowed them to escape predation since early on?other echinoderms were only able to live infaunally during the Marine Mesozoic Revolution, about 250 million-years later. This project aims to improve our knowledge of the holothuroid fossil record by describing the systematic composition and morphology of Brazilian specimens. Grant Paleontological Society, Sepkoski Grants.