Evolution & Systematics
Calcinus is one of the genera of the second largest family of Paguroidea (hermit crabs), family Diogenidae, which includes most of the medium to large hermit crab species (Malay & Paulay 2009). There are 41 species of Calcinus, all tropical or subtropical,which are identified by the characteristic color patterns (Malay & Paulay 2009). The divergence of Calcinus is considered to be largely as a result of allopatric speciation with the conspicuous color patterns evolved rapidly as the adaptive visual cues (Malay & Paulay 2009). In the Central Pacific, the sea-level changes in Pleistocene may have contributed to the speciation process by the changes in size and quality of the habitats, but not by their impact on the dispersal distances (Baums et al 2013). The strong dispersal of Calcinus species is supported by the genetic homogeneity of the wide-ranging species including C. latens, and their reach to the remote islands (Malay & Paulay 2009). The pattern of diversification of Calcinus is unique in that it does not centre the Indo-Malayan area, where endemics of many other marine taxa are likely to emerge, but peaks at the Mariana and Tuamotu Islands in Oceania(Malay & Paulay 2009). This pattern may be the result of the ecological limitation on this genus which prefers oceanic habitat to continental shorelines (Malay & Paulay 2009).
Malay and Paulay (2009) provided the detailedphylograms of Calcinus based on theirmolecular analysis: This is the general picture of Calcinus species relationships based on their data.
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Evolutional relationships between Calcinus species: C. latens makes an early clade within the genus.
(Figure produced based on the data from Malay & Paulay 2009)
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