Multilocus phylogeny and historical biogeography of the Crematogaster inflata-group (Hymenoptera: Formicidae) in South-East Asia Author Hosoishi, Shingo Author Maruyama, Munetoshi Author Yamane, Seiki Author Jaitrong, Weeyawat Author Hashim, Rosli Author Syaukani, Syaukani Author Sokh, Heng Author Itioka, Takao Author Meleng, Paulus Author Pham, Thai Hong text Zoological Journal of the Linnean Society 2023 2023-07-01 198 3 901 922 https://academic.oup.com/zoolinnean/article/198/3/901/7197147 journal article 10.1093/zoolinnean/zlad005 0024-4082 8141964 IS CREMATOGASTER SUBCIRCULARIS A RELICT SPECIES ? Crematogaster subcircularis was revealed to have an interesting distribution pattern. This species is found in mountainous areas ( 600–1250 m elevation) of the Sundaic region: the Malay Peninsula (Fraser’s Hill, 1000 m ), Borneo (Poring, 600–700 m ; Crocker Range, 1100 m ) and Java (Cikaniki, 1000–1250 m ). This distribution suggests that the ancestor retreated to high-altitude forests during the ice age, whereas the other related species ( C. modiglianii ) remained in lowaltitude forests ( 0–600 m elevation). Despite a postulated savannah corridor through central Sundaland ( Bird et al. , 2005 ) that might have restricted the west– east dispersal of forest species, gallery forests in the Sunda Shelf could have served as corridors for forest species and facilitated the dispersal of C. subcircularis ( Fig. 4 ). Rising sea-levels in the Late Pleistocene may have isolated the three populations. Molecular dating estimates and restricted highland distribution imply that C. subcircularis is a relict species. Several studies have hypothesized that continuous mountain ranges, which span Myanmar , Thailand , Laos , south China and Vietnam , acted as glacial refugia ( Brandon-Jones, 1996 ; Gorog et al. , 2004 ; Iyengar et al. , 2005 ). Assuming that C. subcircularis is a relict with a wide distribution range in the glacial periods, those populations were fragmented into several geographical ones when the sea level was higher, then closely related or sister-species might have retreated to the high-elevation refugia of mainland South-East Asia ( Surridge et al. , 1999 ).