Simbakubwa

Simbakubwa Temporal range: early Miocene
reconstruction of Simbakubwa kutokaafrika
size comparison to human
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	†Hyaenodonta
Superfamily:	†Hyainailouroidea
Family:	†Hyainailouridae
Subfamily:	†Hyainailourinae
Genus:	†Simbakubwa Borths & Stevens, 2019
Type species
†Simbakubwa kutokaafrika Borths & Stevens, 2019

Simbakubwa ("great lion") is an extinct genus of hyainailourid hyaenodonts from paraphyletic subfamily Hyainailourinae that lived in Kenya during the early Miocene.

Etymology

The name of this genus comes from Swahili language for "great lion". 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 280 kg (620 lb), comparable to the largest lions, to an upper estimate possibly reaching up to 1,500 kg (3,300 lb), which would surpass the modern polar bear in size.

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. 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 study of the postcranial remains indicates Simbakubwa was possessed of a semi-digitigrade walking stance.

Paleoecology

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.

Phylogeny

The phylogenetic relationships of genus Simbakubwa are shown in the following cladogram:

†Hyaenodonta	†Eoproviverra †Boualitomidae †Arfiidae †Limnocyonidae †Sinopidae †Hyaenodontoidea †Gazinocyon †Pyrocyon †Galecyon  †Afro‑Arabian clade  †Indohyaenodontidae †Glibzegdouia †Parvavorodon †Koholiidae †Tritemnodon †Furodon †Kyawdawia †Paratritemnodon †Teratodontidae †Hyainailouroidea †Apterodontinae †Orienspterodon †Hyainailourinae †Hemipsalodon  ?  †Ischnognathus †Akhnatenavus clade †Akhnatenavus †Paroxyaenini †"Pterodon" sp. (BC 15’08) †Hyainailourinae sp. (UON 84-359) †Hyainailourinae sp. C (DPC 9243 & DPC 10315) †Hyainailourinae sp. D (DPC 6545) †Hyainailourinae sp. A (DPC 6555) †"Pterodon" africanus †Parapterodon †"Pterodon" sp. (DPC 5036) †"Pterodon" phiomensis †Hyainailourini †Kerberos †"Pterodon" syrtos †Pterodon clade †Pterodontina †Falcatodon †Sectisodon †Exiguodon †Isohyaenodon zadoki †Isohyaenodon  (†Isohyaenodontina) †Isohyaenodon andrewsi †Sivapterodon †Hyainailouros bugtiensis †Hyainailouros napakensis †Hyainailouros †Hyainailouros sulzeri †Hyainailourinae sp. (GSN AD 100’96)  †Simbakubwa  †Simbakubwa kutokaafrika †Leakitheriini †Megistotherium †Mlanyama †Metapterodontini †Pakakali †Prionogalidae	†Lahimia clade †Arfia clade †Galecyon clade †Indohyaenodon clade †Tritemnodon clade †Kyawdawia clade †Hyainailouridae