Paratrichocladius, Santo-Abreu, 1918

Krosch, Matt N., Cranston Fls, Peter S., Baker, Andrew M. & Vink, Sue, 2015, Molecular data extend Australian Cricotopus midge (Chironomidae) species diversity, and provide a phylogenetic hypothesis for biogeography and freshwater monitoring, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 175 (3), pp. 496-509 : 503-505

PARATRICHOCLADIUS

The molecular phylogeny presented here and the morphological assignments of individuals to species were in close agreement, a trend that is well supported in chironomid research (e.g. Cranston et al., 2010; Krosch et al., 2011). Only three genetically divergent taxa were observed that did not fit the previous keys, represent- ed by nine individuals within the total molecular data set of 200 individuals (although three additional individuals from the divergent form of C. annuliventris were sequenced for COI, but could not be included in the phylogeny). This is despite much broader geographical sampling in this study relative to HPD, highest posterior density.

previous work, and demonstrates that recently reassessed morphological diagnostics are largely reliable. Moreover, close examination of the divergent forms of both C. parbicinctus and C. annuliventris have revealed subtle morphological differences that have since been integrated into a revised key ( Drayson et al., 2015). Although we accept that these taxa may represent additional ‘cryptic’ species of Cricotopus , too many lacunae (e.g. all were represented by larvae only) currently exist to justify formal description.

Perhaps the most surprising outcome of the molecular phylogeny was the observed paraphyly of Cricotopus with regard to Paratrichocladius . All sampled Paratrichocladius taxa were larvae, except for a single adult male, and initial identification of the larvae was as C. brevicornis under a previous key ( Cranston, 1996). Only after closer examination were subtle morphological differences apparent (see Cranston & Krosch, 2015, in press), and thus larvae for the two recognized Paratrichocladius species are included near to C. brevicornis (now C. draysoni Cranston & Krosch ) in the revised key of Drayson et al. (2015). Rigorous morphological assessment of type material across all life stages from voucher collections has prompted the synonymization with Paratrichocladius into Cricotopus as a subgenus ( Cranston & Krosch, 2015). The strongly supported sister relationship between Paratrichocladius and the C. albitibia group was somewhat unexpected, given the larval morphology; however, given the inclusion of African Paratrichocladius and both African and Asian C. albitibia we believe the result is sound. Future studies would benefit from the inclusion of Holarctic members of both genera, as this is widely acknowledged as the centre of diversity for both genera.