Triasacarus
| Triasacarus | ||||||||||||
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| Temporal occurrence | ||||||||||||
| Upper Triassic (Late Carnian ) | ||||||||||||
| 230 million years | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Triasacarus | ||||||||||||
| Lindquist & Grimaldi , 2012 | ||||||||||||
| Art | ||||||||||||
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Triasacarus is an extinct genus of mites (Acari). Their only species, Triasacarus fedelei , lived around 230 million years ago in the late Triassic . It had a worm-shaped body about 0.21 mm long and - unlike all mites today - ungrown mouthparts . Triasacarus fedelei was found in the amber of the Holy Cross formation in Belluno , Italy . Unlike many of his relatives living today from the superfamily Eriphyoidea , they did not feed on flowering plants , but on conifers . The genus and species were first described in 2012 by David Grimaldi and Evert Lindquist , who classified Triasacarus as a very original representative of the gall mite relatives.
features
Triasacarus had an elongated, worm-shaped body about 0.21 mm long. Be a long proboscis occupied gnathosoma has from the bases of palp coxae framed on which the freely movable palps sat. On the back, Triasacarus had a pair of pointed structures that may represent jaw claws . The spine shield had a head-side extension and was equipped with a pair of bristles on the rear and side-front side. Triasacarus had an opisthosoma divided into 55–60 fine annuli . Each annulus was studded with a series of small needles. Laterally a long pair of bristles grew at the level of the 24th and 38th annulus (d and e); At the end of the body Triasacarus also had subcaudal (f) and caudal bristles (h1 and h2). Both the rear and the front pair of legs of the animals had feather bristles with branched shafts at the ends. There was one long bristle on the femur and one on the genus, and two on the tibia. The tarsi had short bristles. The second pair of legs may have solenidia (sensory bristles) on the tibia and tarsus. The third and fourth pair of legs were missing from Triasacarus .
Site and fossil material
The holotype and so far the only find of Triasacarus comes from Triassic amber of the Holy Cross formation west of Cortina d'Ampezzo . The find layer is dated to the Upper Triassic level of the Carnian and is around 230 million years old. The amber consists of fossil resin of the extinct conifer family Cheirolepidiaceae , possibly of the genera Brachyphyllum or Pagiophyllum .
Way of life
The fact that Triasacarus was preserved in resin droplets suggests that the genus was mites that fed on the leaves of conifers (Cheirolepidiaceae species). Such a way of life occurs in the Eriophyoidea only in a few cases today. Most of the representatives of this group feed on Bedecktsamern , which did not appear until the Cretaceous . Recent mites with worm-shaped bodies usually form galls that protect them from loss of fluid; this may also apply to Triasacarus .
Taxonomy and systematics
Triasacarus fedelei was first described in 2012 as the only species of the genus Triasacarus . The authors of the first description, David Grimaldi and Evert Lindquist , chose a combination of Trias and Acarus , the type genus of the mites , as the generic name . The specific epithet honors Paolo Fedele, who discovered the extensive amber deposits near Cortina d'Ampezzo. The holotype ( inventory number MPG 31343) comes from a collection of 70,000 amber drops that the palaeontologists and their colleagues searched for inclusions over a period of seven years.
Among other things, the feathered legs, their bristles and the worm-shaped body identify Triasacarus as a member of the Eriophyoidea, one of the most original groups of mites. According to Grimaldi and Lindquist, the free-standing mouthparts indicate that Triasacarus is more original than all species of the group living today, which consistently have at least partially overgrown mouthparts.
swell
literature
- Alexander R. Schmidt, Saskia Jancke, Evert E. Lindquist, Eugenio Ragazzi, Guido Roghi, Paul C. Nascimbene, Kerstin Schmidt, Torsten Wappler, David A. Grimaldi: Arthropods in Amber from the Triassic Period. In: Proceedings of the National Academy of Sciences . Vol. 109, No. 37, 2012, pp. 14796-14801, doi : 10.1073 / pnas.1208464109 .
Individual evidence
- ↑ Schmidt et al. 2012, pp. 12–3.
- ↑ Schmidt et al. 2012, pp. 2–3.
- ↑ a b Schmidt et al. 2012, p. 1.
- ↑ a b Schmidt et al. 2012, p. 5.
Web links
- Oldest arthropod discovered in the world ( memento from August 30, 2012 in the Internet Archive ), article with picture series and video contribution. NDR 2012