Dactylosaurus is a genus of nothosaur in the family Pachypleurosauridae. Along with Anarosaurus, Dactylosaurus was one of the earliest known pachypleurosaurs to come from Europe.Lepidosauromorpha: Pachypleurosauridae: Dactylosaurus & Anarosaurus Palaeos.com. Last accessed 2008-07-04.
Etymology Dactylosaurus comes from the Greek (), "finger" and (), meaning "lizard" or "reptile."
Description Dactylosaurus was a small reptile measuring up to long. The nasal bones of Dactylosaurus meet and are broadly structured.Rieppel, O & L Kebang (1995), "Pachypleurosaurs (Reptilia, Sauropterygia) from the Lower Muschelkalk, and a review of the Pachypleurosauroidea." Fieldiana Geol. N.S. 32: 1-44. The upper temporal fenestra is large and kidney-shaped. There are 17 cervical vertebrae and the cervical ribs have anterior processes. The maxillae of Dactylosaurus extended broadly up the side of the snout.
D. gracilis The holotype specimen (MGUWR WR 3871s) of D. gracilis was only a partial skeleton, consisting of the anterior end alone. Because it differed slightly from the fossils of D. gracilis, it was first thought to belong to the species D. schroederi, which is now considered a junior synonym for juvenile D. gracilis. Once this was established, the juvenile fossil, which was found before the adult fossils, became the holotype. The one limb that was found (a left forelimb), was noted to have a slimmer radius and ulna than Neusticosaurus, a similar nothosaur from Europe. D. gracilis is the smallest known species in its family, which includes the much more recognized Keichousaurus, a nothosaur often remembered for its small size. The original holotype of D. gracilis is considered a juvenile, however the size of a nothosaur when its bones harden is used to show size, making the estimate as smallest member of its family still valid.
Distribution
Dactylosaurus lived in the Early and Middle Triassic period during the Late Olenekian and Anisian faunal stage, of central Europe.
In terms of geology, they are found: 1) in the uppermost Röt (uppermost Buntsandstein; Lower Triassic): e.g. Michałkowice (Siemianowice Śląskie) and Kamień Śląski, S Poland, (the second location is not sure because Röt is not exposed there), 2) in the lowermost Muschelkalk (Middle Triassic), inter alia in the Gogolin Formation - Gogolin and its vicinity, S Poland.Sues H-D., Carroll R.L. 1985. The pachypleurosaurid Dactylosaurus schroederi (Diapsida: Sauropterygia). Canadian Journal of Earth Sciences 22(11): 1602-1608
In 2012, the new Röt site (~ 247 Ma; Lower Triassic; the latest Olenekian) with abundant disarticulated remains of Dactylosaurus was found in Gogolin. Presently, this in the only site where Dactylosaurus remains are accessible to collect.Kowal-Linka M., Bodzioch A. 2012a. Warstwy kościonośne z Dactylosaurus (Reptilia, Sauropterygia) z retu (trias dolny, olenek) Opolszczyzny Bonebeds with Dactylosaurus (Reptilia, Sauropterygia) from the Röt (Lower Triassic, Olenekian) in the Opole Silesia region (S Poland). Przegląd Geologiczny 60 (12): 646–649Kowal-Linka M., Bodzioch A. 2012b. New findings of vertebrate remains from the Röt (Lower Triassic, Olenekian) in the vicinity of Gogolin (Opole Silesia, S Poland). [W:] Krasiejów - inspiracje paleontologiczne / Krasiejów - paleontological inspirations. E. Jagt-Yazykova, J. Jagt, A. Bodzioch, D. Konietzko-Meier (red.). Zakład Poligraficzno-Wydawniczy "Plik", Bytom: 70-80. Kowal-Linka M., Bodzioch A. 2017. Genesis of the Lower Triassic bonebeds from Gogolin (S Poland): The impact of microbial mats on trapping of vertebrate remains. Palaeogeography, Palaeoclimatology, Palaeoecology 466, 38–58
References
External links Pachypleurosauridae from Palaeos.com (technical) Dactylosaurus from the Plesiosaur Directory http://www.nrcresearchpress.com/doi/abs/10.1139/e85-169 Kowal-Linka & Bodzioch 2012a Kowal-Linka & Bodzioch 2012b