Rosamygale

Rosamygale; Temporal range: Anisian PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Class:	Arachnida
Order:	Araneae
Infraorder:	Mygalomorphae
Genus:	†Rosamygale; Selden & Gall, 1992[1]
Species:	†R. grauvogeli
Binomial name
	†Rosamygale grauvogeli; Selden & Gall, 1992[1]

Rosamygale is an extinct genus of Triassic spiders, with a single described species, Rosamygale grauvogeli.[1] It is the oldest known member of Mygalomorphae, one of the three main divisions of spiders, which includes well known forms such as tarantulas and Australian funnel-web spiders.[2] It was described by Selden and Gall in 1992, from specimens found in the Middle Triassic (Anisian ~ 247-242 million years ago) aged Gres a Meules and Grès à Voltzia in France.[1][3] It is also considered to be the oldest known member of the Avicularioidea, one of the two main divisions of Mygalomorphae.[4]

Description

Rosamygale is known from compression fossils consisting of brown coloured organic cuticle remains of several juvenile and adult individuals, up to 6 mm in length.[3]

Phylogeny

In the original description, Rosamygale was placed in Hexathelidae, with reservations.[3] However, later studies noted that it was placed in the family based on characters which are plesiomorphic (ancestral) for many groups of mygalomorphs. It can be securely placed in Avicularioidea, one of the two major groupings of mygalomorph spiders based on the on the absence of an abdominal scutum and well-separated posterior lateral spinnerets.[4]

Palaeoenvironment

The sediments that the spiders were discovered in represents a deltaic environment, with the fossil found it what likely was a stagnant brackish pond that filled during the rainy season, surrounded by sparse vegetation.[3] Associated terrestrial fauna includes scorpions, myriapods and insects. With an associated aquatic fauna containing the brachiopod Lingula, clam shrimps and fish. The authors speculated that, due to the nature of the locality, that Rosamygale burrowed into or near the banks of watercourses.[3]

References

Dunlop, J.A.; Penney, D. & Jekel, D. (2017), "A summary list of fossil spiders and their relatives, version 19" (PDF), World Spider Catalog, Natural History Museum Bern, retrieved 20 July 2017
Fossil Arachnids Page 120 Jason A. Dunlop, David Penney - 2012
Selden, Paul A. & Gall, Jean-Claude (1992), "A Triassic mygalomorph spider from the northern Vosges, France" (PDF), Palaeontology, 35 (1): 211–235, retrieved 20 July 2017
Magalhaes, Ivan L. F.; Azevedo, Guilherme H. F.; Michalik, Peter; Ramírez, Martín J. (2020). "The fossil record of spiders revisited: implications for calibrating trees and evidence for a major faunal turnover since the Mesozoic". Biological Reviews. 95 (1): 184–217. doi:10.1111/brv.12559. ISSN 1464-7931.

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[DunlPennJeke17-1] Dunlop, J.A.; Penney, D. & Jekel, D. (2017), "A summary list of fossil spiders and their relatives, version 19" (PDF), World Spider Catalog, Natural History Museum Bern, retrieved 20 July 2017

[2] Fossil Arachnids Page 120 Jason A. Dunlop, David Penney - 2012

[SeldGall92-3] Selden, Paul A. & Gall, Jean-Claude (1992), "A Triassic mygalomorph spider from the northern Vosges, France" (PDF), Palaeontology, 35 (1): 211–235, retrieved 20 July 2017

[:0-4] Magalhaes, Ivan L. F.; Azevedo, Guilherme H. F.; Michalik, Peter; Ramírez, Martín J. (2020). "The fossil record of spiders revisited: implications for calibrating trees and evidence for a major faunal turnover since the Mesozoic". Biological Reviews. 95 (1): 184–217. doi:10.1111/brv.12559. ISSN 1464-7931.