This species is only known from the western side of the Nguru Mountains, in the Morogoro region of Tanzania (Menegon et al. 2011). It was collected from two sites in the same geographical locality, which is herein considered as a single threat-defined location. The recent description of numerous distinct species of Callulina, each with very restricted distributions on particular mountain ranges (Loader et al. 2010, 2011) suggests that it is unlikely to be much more widespread. This frog has been recorded at elevations between 1,950-2,100 m asl, but calls were heard up to 2,200 m asl (S. Loader pers. comm. November 2011). If it is genuinely confined to this elevational band the frog's extent of occurrence (EOO) will be below 100 km2, but no more precise estimate is currently possible (S. Loader pers. comm. November 2011). It appears to form part of an upper montane Nguru fauna characterized by endemic species that are not found at lower elevations (Loader et al. 2011). It is partly sympatric with C. hanseni (Loader et al. 2010a), and its distribution is similar to that reported for Arthroleptis nguruensis (Poynton et al. 2008).
Habitat and Ecology
It seems to be restricted to the montane and upper montane forest of the Nguru South Forest Reserve (Menegon et al. 2008), and it is likely to be dependent on primary forest (S. Loader pers. comm. November 2011). Individuals have been found during the day by digging in soft soil and leaf litter accumulating at the base of large trees (S. Loader pers. comm. November 2011). This microhabitat together with the presence of strongly keratinized and well-raised metatarsal tubercles is suggestive of semifossoriality (S. Loader pers. comm. November 2011). The species is presumed to be oviparous with direct development on the basis of the presence of large eggs found in the oviduct of a dissected female (S. Loader pers. comm. November 2011). Although no direct evidence is known for the genus Callulina, oviparity with direct development is regarded as the most likely reproductive mode for this genus of brevicipitids (Müller et al. 2007).
It has been recorded in two surveys, one in 2004 and the other in 2008 (S. Loader pers. comm. November 2011). It was relatively common in both survey periods (Menegon et al. 2011). There is no other information on population densities in this species, and the population trend is unknown.
Cardamom and yams are cultivated at high elevations in the Nguru Mountains, and cardamom production is widespread within Nguru South Forest Reserve (Menegon et al. 2008). Although there is no evidence of major disturbances such as slash-and-burn agriculture, there is continuing pressure on the forest resulting from growth of the surrounding human population (S. Loader pers. comm. June 2011), and this is particularly intense around the borders of Nguru South Forest Reserve, with forests outside the reserve boundary having declined by over 60% between 1975 and 2003 (Doggart and Loserian 2007). The extent and impacts of forest decline in areas potentially inhabited by this frog are difficult to evaluate (S. Loader pers. comm. June 2011), but its restricted distribution puts it at high risk from even small changes in forest cover.
The species is found in a proposed nature reserve, Mkingu Nature Reserve, which comprises the previously named Nguru South and Mkindo Forest Reserves (S. Loader pers. comm. April 2012). Currently, enforcement of this protection is limited (S. Loader pers. comm. June 2011). The protected status of this reserve is likely to be improved by designating it a nature reserve, and the site needs to be managed to enforce the new protection and limit the impacts of human activities on remaining primary forest (S. Loader pers. comm. June 2011). Further research is needed, to establish whether this frog occurs at lower elevations than is currently known, and to clarify its ecological requirements and exposure to threats.
Red List Status
Critically Endangered (CR)
Listed as Critically Endangered on the basis that it is known from a single location defined by ongoing pressure from human expansion into formerly forested land, its extent of occurrence (EOO) is estimated to be below 100 km2, and there is a continuing decline in the quality and extent of its forest habitat in the Nguru Mountains.
Populations of Callulina from the Nguru Mountains were historically assigned to C. kreffti, as then understood a widespread East African montane species and the sole member of the genus. Menegon et al. (2008) recognized four distinct species among Nguru Mountains Callulina, two of which have since been formally described (Loader et al. 2010). One of these, C. kanga, appears to be restricted to the Kanga Forest Reserve (Menegon et al. 2008, Loader et al. 2010). The remaining three species are confined to blocks within the Nguru South Forest Reserve (Menegon et al. 2008, Loader et al. 2010). The name C. hanseni refers to "Callulina sp. 2" of these authors (Loader et al. 2010); the remaining populations are included within the Red List account for C. kreffti pending further research.
IUCN SSC Amphibian Specialist Group, 2013. Callulina meteora. The IUCN Red List of Threatened Species 2013: e.T202410A2744064. http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T202410A2744064.en .Downloaded on 10 December 2018