Tasbacka

{{Short description|Extinct genus of turtles}}

{{Automatic taxobox

| fossil_range = Campanian-Eocene, {{fossilrange|Campanian|48.6|ref=}}

| image = Tasbacka danica.JPG

| image_caption = T. danica fossil from the Fur Formation

| taxon = Tasbacka

| authority = Nessov, 1987

| type_species = Tasbacka aldabergeni

| type_species_authority = Nessov, 1987

| subdivision_ranks = Other species

| subdivision =

• Tasbacka danica Karl & Madsen, 2012
• Tasbacka germanica Karl, Gröning & Brauckmann, 2019
• Tasbacka ouledabdounensis Tong & Hirayama, 2002
• Tasbacka ruhoffi Weems, 1988
• Tasbacka salisburgensis Karl, 1996

}}

Tasbacka is an extinct genus of sea turtle containing several species.{{ cite journal |author1=Karl, H.-V. |author2=Madsen, H. |year=2012 |title=Tasbacka danica n. sp., a new Eocene marine turtle of Denmark (Testudines: Chelonioidea) |journal=Studia Palaeocheloniologica |volume=4 |pages=193–204 |url=http://seaturtle.org/library/KarlH-V_2012e_StudiaPalaeocheloniologica.pdf }}

Though the type species, T. aldabergeni, has only been found in Kazakhstan,{{cite web |title=†Tasbacka aldabergeni Nessov 1987 (sea turtle) |url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=264912 |work=Paleobiology Database |publisher=Fossilworks }} Tasbacka had a wide distribution. T. ruhoffi was found in the eastern USA,{{cite web |title=†Tasbacka ruhoffi Weems 1988 (sea turtle) |url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=316510 |work=Paleobiology Database |publisher=Fossilworks }} T. danica in modern Denmark, T. ouledabdounensis in modern Morocco, T. salisburgensis in modern Austria, and T. germanica in modern Germany.{{cite journal |last1=Karl |first1=H.-V. |last2=Gröning |first2=E. |last3=Brauckmann |first3=C. |year=2019 |title=Tasbacka germanica n. sp., a new Campanian marine turtle from NW-Germany (Testudines: Chelonioidea) |journal=Mainzer Naturwissenschaftliches Archiv |volume=56 |pages=99–112 }}

In 2008, researchers found a well-preserved, juvenile specimen of T. danica in Denmark's Fur Formation.{{cite web |last1=Peake |first1=Tracey |title=Keratin, Pigment, Proteins From 54 Million-Year-Old Sea Turtle Show Survival Trait Evolution |url=https://news.ncsu.edu/2017/10/schweitzer-sea-turtle/ |website=NC State University News |publisher=North Carolina State University |date=October 17, 2017}} Some of the fossil's soft tissues remained.{{cite web |title=Danekræ fossil trove collection |url=https://samlinger.snm.ku.dk/toer-og-vaadsamlinger/geologi/danekrae-fossil-trove-collection/ |website=Statens Naturhistoriske Museum Samlinger |language=Danish |quote="A complete juvenile sea-turtle referred to the new species Tasbacka danica, with soft tissue preservation and outstanding exhibition value."}} The specimen, dating back to 54 Ma, contained eumelanin. This pigment would've given the hatchling a dark shell while it was alive. Modern sea turtle hatchlings also have dark shells; while a hatchling floats on the ocean's surface, its dark coloring enables it to absorb heat from the sun and avoid predatory birds. The existence of similar pigment on an ancient specimen suggests sea turtles evolved this survival trait millions of years ago.