| Laomaki | |
|---|---|
Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Primates |
| Suborder: | Strepsirrhini |
| Family: | †Sivaladapidae |
| Genus: | †Laomaki Niet al., 2016 |
| Type species | |
| †Laomaki yunnanensis Niet al., 2016 | |
Laomaki is a genus ofadapiform primate that lived during theEarly Oligocene in Asia, containing only the speciesLaomaki yunnanensis. It was described from a rightmaxilla fragment. Its molars and premolars are somewhat similar to those ofRencunius andAnthradapis respectively. Its placement within the familySivaladapidae is uncertain; it has not been placed in asubfamily. It has been found at sites inJammu and Kashmir andYunnan, having lived around the time of theEocene–Oligocene transition.
Thetype species ofLaomaki,L. yunnanensis, was first described by Xijun Ni, Qiang Li, Lüzhou Li, andK. Christopher Beard in 2016 from a rightmaxilla fragment found at theEarly Oligocene Lijiawa fossil site, part of the Caijiachong Formation inYunnan Province, China. The generic name comes from the Mandarin wordlao (lit. 'old') and the Malagasy wordmaky (lit. 'lemur'), while the specific name is in reference to the geographic location of the remains.[1] As of 2023, no additional species ofLaomaki have been described.[2]
Unlike any othersivaladapid besidesRencunius,Laomaki has strongly developed conules on its uppermolars. Both the upper and lower molars ofLaomaki differ from those of the former taxon in their extremely crenulatedenamel, pyramidalcusps, and sharper crests. The upper molars are also more transverse than those ofRencunius, with pyramidal conules as opposed to bulbous ones, and its hypocones (small cusps found on mammalian upper molars) are smaller. The P4 and P4 premolars are less molarized than those ofYunnanadapis andMiocene sivaladapids.[1] Its premolars were also compared to those ofAnthradapis in the latter's taxonomic description.[3] It has an estimated body mass of 188 grams (6.6 oz).[4]
Laomaki belongs to the familySivaladapidae, a group ofadapoid primates whose relationship with other taxonomic groups remains uncertain; they are possibly close relatives of the Europeancercamoniids. The placement ofLaomaki within the family is unknown, making the genusincertae sedis. A 2017 phylogenetic study found support for aclade within Sivaladapidae containing thebasal generaLaomaki,Hoanghonius,Paukkaungia, andKyitchaungia. While the original description ofLaomaki found it to be intermediate between the generaHoanghonius andRencunius, the aforementioned 2017 study foundLaomaki closer toHoanghonius, assister taxa.[4]
Theholotype of the genusLaomaki was found instrata of Early Oligocene age in Yunnan, about 34 million years old. This coincides with theEocene-Oligocene transition, an episode of cooler and drier climactic conditions that led to theextirpation ofprimates in North America and Europe. Still, several clades of primates managed to persist in Asia, Sivaladapidae among them. In China, Myanmar, and Thailand,anthropoids dominate theLate Eocene primate fossil record; by contrast, only one of six primates known from the Early Oligocene in Yunnan is a member of the group, while multiple sivaladapid genera, includingLaomaki, have been discovered.[1] Specimens have also been found in the Lower Siwalik deposits near the town ofRamnagar inJammu and Kashmir, with a mean age estimate ofc. 33 million years.[4]
Within China,Laomaki is known solely from the Ulantatalian stage (a Chineseland mammal age for fossils of Early Oligocene age named after the Ulantatal area inInner Mongolia). Other mammalian taxa known exclusively from this stage include theartiodactylsEumeryx culminis andPraetragulus gobiae; thelagomorphsDesmatolagus pusillus,D. youngi, andOrdolagus teilhardi; thehyaenodontHyaenodon neimongoliensis; theerinaceomorphPalaeoscaptor acridens; the other primatesYunnanadapis folivorus,Y. imperator,Gatanthropus micros,Bahinia banyueae, andOligotarsius rarus; and over twenty species ofrodents belonging to various genera.[5] Early Oligocene mammal taxa recovered specifically from the Lijiawa fossil site includePtilocercus kylin (atreeshrew),Gigantamynodon giganteus,Cricetops, andEucricetodon.[6]
During the Eocene-Oligocene transition, the physical environment of Asia changed significantly as a result ofaridification, with open grasslands replacing forests, although a 2020 study found that this change in climate may have had a less dramatic effect on fauna than previously thought.[5] On a geographic scale, theParatethys Sea retreated from Central Asia, the uplift of theHimalayas continued, and theSouth China Sea opened.[1]
