Marginix

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Marginix
Temporal range: Early Devonian–Late Devonian
Marginix yachalensis holotype.jpg
Illustration of the holotype specimen of M. yachalensis
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Echinodermata
Class: Ophiuroidea
Family: Encrinasteridae
Subfamily: Encrinasterinae
Genus: Marginix
Martínez & del Río, 2015
Type species
Encrinaster yachalensis
(= †Marginix yachalensis)
Ruedemann, 1916
Other species
  • M. hilleriJell & Theron, 1999
  • M. notatusFraga & Vega, 2020
Synonyms
Synonyms of Marginix
Synonyms of M. yachalensis
  • Encrinaster yachalensisRuedemann, 1916
  • Marginaster yachalensisHaude, 1995
  • Marginura yachalensisHaude, 1999
Synonyms of M. hilleri
  • Marginura hilleriJell & Theron, 1999

Marginix is an extinct genus of brittle star in the family Encrinasteridae that lived during the Devonian period in South America and Africa. It contains three named species. The type species, M. yachalensis, was originally named as a species of Encrinaster in 1916, and its remains are known from Argentina. A second species, M. hilleri, was first described in 1999 based on specimens from South Africa, and a third species, M. notatus, originates from Brazil and was named in 2020. Fossils of Marginix were first recognized to represent a distinct genus in 1995, but the genus was only given its current name in 2015. Prior to this, it was given the names Marginaster and Marginura, but both were preoccupied and had to be replaced.

Contents

Discovery and naming

In 1916, a study by Rudolf Ruedemann describing some fossil material sent from Cerro Blanco, Jachal, Argentina to John Mason Clarke at the New York State Museum was published. The fossils, then thought to represent starfish remains, were recognized by Ruedemann to represent two new species, one of which he thought was a member of the genus Encrinaster and named Encrinaster yachalensis, the specific name referring to Jachal. Ruedemann studied a single specimen of this species, exhibiting the abactinal side of the animal, cataloged as NYSM 7762 and designated as the holotype of the species. [1] Later in 1995, Reimund Haude discovered that this species, now known to be a brittle star, differs significantly from other species of Encrinaster, and thus transferred it to a new genus which he named Marginaster. The species was thus renamed as Marginaster yachalensis, and became the type species of its genus. [2] Haude would later be made aware that the name Marginaster was preoccupied by a starfish in the Poraniidae family named by Edmond Perrier in 1881, and therefore renamed the genus to Marginura in 1999. [3] However, this name was also preoccupied, as it had already been given by Max Sellnick to a mite in 1926. Realizing this, Sergio Martínez and Claudia del Río renamed the genus again to Marginix in 2015. [4]

Species

The following species are currently assigned to the genus Marginix:

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References

  1. 1 2 3 Ruedemann, Rudolf (1916). "Two new starfishes from the Silurian of Argentina". New York State Museum Bulletin. 189: 116–120.
  2. Haude, Reimund (1995-07-14). "Lower Devonian echinoderms from the Precordillera (Argentina)". Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen. 197 (1): 37–86. doi:10.1127/njgpa/197/1995/37. ISSN   0077-7749.
  3. Haude, Reimund (1999-05-26). "Der - verzögerte - Ersatz eines Homonyms: Marginaster Haude 1995". Neues Jahrbuch für Geologie und Paläontologie - Monatshefte. 1999 (5): 292–294. doi:10.1127/njgpm/1999/1999/292. ISSN   0028-3630.
  4. 1 2 3 Martínez, Sergio; Río, Claudia del (2015). "Fossil Asterozoa (Echinodermata) of Argentina". Revista de Biología Tropical. 63 (2): 1–6. doi:10.15517/rbt.v63i2.23123.
  5. Jell, Peter A.; Theron, Johannes N. (1999). "Early Devonian echinoderms from South Africa". Memoirs of the Queensland Museum. 43: 115–199.
  6. Fraga, Malton Carvalho; Vega, Cristina Silveira (2020-01-01). "Asterozoans from the Devonian of the Paraná Basin, South Brazil". Journal of South American Earth Sciences. 97: 102398. doi:10.1016/j.jsames.2019.102398. ISSN   0895-9811.