Browsing by Author "Ngalason, Wilirk"

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    A New Dwarf Forest Toad (Amphibia: Bufonidae: Nectophrynoides) from the Ukaguru Mountains, Tanzania
    (2007) Menegon, Michele; Salvidio, Sebastiano; Ngalason, Wilirk; Loader, Simon P.
    A new species of Nectophrynoides from the Ukaguru Mountains, Eastern Arc Mountains Tanzania, is described. The new species is diagnosed by the presence of large prominent spines with keratinized tips, positioned on the dorsum, head and limbs. In addition, the combination of the following characters -presence of large tympanum and annulum, foot longer than tibia, the lack of parotoid glands and advertisement call features, allow this species to be distinguished from all other species in the genus. The new species adds to our understanding of the amphibian fauna of the Ukaguru Moun-tains, relatively undersampled and poorly understood.
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    Reproduction in Brevicipitid Frogs (Amphibia: Anura: Brevicipitidae)—Evidence from Probreviceps M. Macrodactylus
    (2007) Müller, Hendrik; Loader, Simon P.; Ngalason, Wilirk; Howell, Kim M.; Gower, David
    An egg clutch of the Tanzanian brevicipitid frog, Probreviceps m. macrodactylus, is described for the first time. The single clutch consists of 32 eggs and 21 infertile, jelly-filled capsules, tightly bound together by a thin, tough outer layer. The infertile capsules are concentrated toward the top of the clutch. The eggs were found in a dry season, and were perhaps likely to hatch at the onset of the short rains. The specific identification is confirmed through analysis of mitochondrial DNA sequence data. Eggs are yolky and large, about 8 mm in diameter (including capsule), suggesting that P. m. macrodactylus has a direct mode of development. The embryos observed were in an early developmental stage and showed the early division of the brain and anlagen of three pairs of visceral arches. Brevicipitid reproduction and development are poorly known, but a review of the existing literature and parsimonious optimization of simple characters onto a phylogenetic framework suggest that direct development is a derived condition characterizing the whole clade.
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    Reproduction in Brevicipitid Frogs (Amphibia: Anura: Brevicipitidae)—Evidence From Probreviceps M. Macrodactylus
    (2007-09) Müller, Hendrik; Loader, Simon; Ngalason, Wilirk; Howell, Kim; Gower, David
    An egg clutch of the Tanzanian brevicipitid frog, Probreviceps m. macrodactylus, is described for the first time. The single clutch consists of 32 eggs and 21 infertile, jelly-filled capsules, tightly bound together by a thin, tough outer layer. The infertile capsules are concentrated toward the top of the clutch. The eggs were found in a dry season, and were perhaps likely to hatch at the onset of the short rains. The specific identification is confirmed through analysis of mitochondrial DNA sequence data. Eggs are yolky and large, about 8 mm in diameter (including capsule), suggesting that P. m. macrodactylus has a direct mode of development. The embryos observed were in an early developmental stage and showed the early division of the brain and anlagen of three pairs of visceral arches. Brevicipitid reproduction and development are poorly known, but a review of the existing literature and parsimonious optimization of simple characters onto a phylogenetic framework suggest that direct development is a derived condition characterizing the whole clade.
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    Three New Species of Callulina (Amphibia: Anura: Brevicipitidae) Highlight Local Endemism and Conservation Plight of Africa's Eastern Arc Forests
    (Wiley, 2010) Loader, Simon P.; Gower, David; Ngalason, Wilirk; Menegon, Michele
    Abstract Material ascribed to the genus Callulina from north-east Tanzania and south-east Kenya is assessed. Three new species of Callulina are described from the North (Callulina laphami sp. nov.) and South (Callulina shengena sp. nov. and Callulina stanleyi sp. nov.) Pare Mountains in Tanzania. The species are diagnosed based on morphological, acoustic, and molecular data. A new key to the species of Callulina is provided. Based on an interpretation of the International Union for Conservation of Nature (IUCN) red list, we suggest that the three species will qualify as critically endangered, because of their small distributions and the ongoing threat to their habitat. We reveal the high local endemism of Callulina in the northern part of the Eastern Arc Mountains, with each species restricted to no more than one mountain (fragment) block. This high local endemism in Callulina is probably widespread across the Eastern Arc, raising further conservation concern for this group of amphibians. Based on new molecular phylogenetic data for Callulina, we discuss biogeographical relationships among north-east Tanzanian mountains, and evolutionary patterns in Eastern Arc breviciptids.