Simbakubwa
{{Short description|Extinct genus of mammals}}
{{Italic title}}
{{Use dmy dates|date=May 2025}}
{{Automatic taxobox
| fossil_range = Early Miocene (Aquitanian) {{fossil_range|23.0|22.0}}
| image = Simbakubwa-kutokaafrika 2.jpg
| image_caption = Reconstruction of
Simbakubwa kutokaafrika
| image2 = Simbakubwa_kutokaafrika.jpg
| image2_caption = Size comparison to human
| display_parents = 3
| taxon = Simbakubwa
| authority = Borths & Stevens, 2019
| type_species = †Simbakubwa kutokaafrika
| type_species_authority = Borths & Stevens, 2019
| synonyms =
}}
Simbakubwa ("great lion") is an extinct genus of hyaenodonts to the family Hyainailourinae that lived in Kenya during the Early Miocene.{{Cite journal |author1=Matthew R. Borths |author2=Nancy J. Stevens |year=2019 |title=Simbakubwa kutokaafrika, gen. et sp. nov. (Hyainailourinae, Hyaenodonta, 'Creodonta,' Mammalia), a gigantic carnivore from the earliest Miocene of Kenya |journal=Journal of Vertebrate Paleontology |volume=39 |issue=1 |pages=e1570222 |doi=10.1080/02724634.2019.1570222|bibcode=2019JVPal..39E0222B |s2cid=145972918 |url=https://figshare.com/articles/journal_contribution/8009951 |url-access=subscription }}
Discovery and Etymology
The fossils of Simbakubwa were first discovered by rural Kenyans at Meswa Bridge, Western Kenya. Thereafter, Matthew Borths and Nancy Stevens published the findings after examining the fossils which had been stored at the Nairobi National Museum in Kenya for decades.{{cite web |last=Zuckerman |first=C. |date=18 April 2019 |title=This new species of ancient carnivore was bigger than a polar bear |url=https://www.nationalgeographic.com/science/2019/04/new-species-ancient-carnivore-was-bigger-than-polar-bear-hyaenodonts/ |archive-url=https://web.archive.org/web/20190418120406/https://www.nationalgeographic.com/science/2019/04/new-species-ancient-carnivore-was-bigger-than-polar-bear-hyaenodonts/ |url-status=dead |archive-date=18 April 2019 |access-date=18 April 2019 |publisher=National Geographic}} The type specimen consists of a mandible from the lower jaw, a right upper maxilla and some postcranial remains. The light wear patterns on the dentition indicate that the holotype specimen was a young adult at the time of its death.
The name of this genus comes from the Swahili language, meaning "great lion". The species name Simbakubwa kutokaafrika means "great lion of Africa”.
Description
Different regression models produce a wide range of body mass estimates for Simbakubwa kutokaafrika: from a low estimate of {{convert|280|kg|lb|abbr=on}}, based on an equation derived from the m3 length of various large carnivorans, comparable to the largest lions, to an upper estimate possibly reaching up to {{convert|1,308|and|1,554|kg|lb|abbr=on}}, based on equations derived from carnassial length of hyaenodonts and m3 length of felids respectively, which would surpass the modern polar bear in size. However, hyainailourids possessed proportionally very large heads in comparison to their body, and postcranial remains indicate that the similar sized Hyainailouros was about the size of a tiger, whereas the larger Megistotherium has been estimated to have reached a maximum weight of {{convert|500|kg|lb}},{{Cite journal |last=Sorkin |first=Boris |date=2008 |title=A biomechanical constraint on body mass in terrestrial mammalian predators |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1502-3931.2007.00091.x |journal=Lethaia |language=en |volume=41 |issue=4 |pages=333–347 |doi=10.1111/j.1502-3931.2007.00091.x|bibcode=2008Letha..41..333S |url-access=subscription }} though this study estimated the body mass of Megistotherium with a low estimate of {{cvt|317|kg|lb}} to higher estimates of {{cvt|1,794|-|3,002|kg|lb}} using the same methods.
The study of the postcranial remains indicates Simbakubwa was possessed of a semi-digitigrade walking stance.
==Paleobiology==
Simbakubwa, like other hyainailourids, probably was a specialist hunter and scavenger that preyed on creatures such as rhinoceroses and early proboscideans. It may have been somewhat less specialized in crushing bone than its later relatives such as Hyainailouros. However, like Hyainailouros, Simbakubwa possessed lingually rotating carnassial blades, ensuring a constant shearing edge throughout its life.
References
{{Reflist}}
{{Pan-Carnivora|H.|state=collapsed}}
{{Taxonbar|from1=Q63203949|from2=Q63203734}}
Category:Fossil taxa described in 2019