Desmopachria striola, Sharp, 1887

Miller, Kelly B. & Wolfe, G. William, 2019, Three New Species in the Desmopachria striola Species-Group of Desmopachria Babington, 1841 (Coleoptera: Adephaga: Dytiscidae: Hydroporinae: Hyphydrini), The Coleopterists Bulletin 73 (3), pp. 621-628: 622-623

publication ID 10.1649/0010-065X-73.3.621

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Desmopachria striola


The Desmopachria striola   species-group

Diagnosis. The Desmopachria striola   speciesgroup is defined as those Desmopachria species   with a distinct sutural stria on the elytron ( Young 1980, 1990; Miller 2001). The group is heterogeneous, and the male genitalia are dissimilar across the entire group as currently defined. Several species, however, including Desmopachria grouvellei Régimbart   , Desmopachria ruginosa Young   , Desmopachria striola Sharp   , and those species described herein seem to have similar genitalia with the median lobe in ventral aspect “shouldered” medially (laterally expanded) to varying degrees and the lateral lobe apically with a more-or-less abruptly obliquely bent flat lobe (e.g., Figs. 3, 4 View Figs ). Even so, this group requires additional investigation to determine if it is natural and what is its diagnostic combination.

Comments. Guignot (1950) described the subgenus Pachriostrix   (type species D. grouvellei   ) to include Desmopachria species   with a distinct sutural stria. Young (1980) retained the definition of the group but noted that the group may well be artificial given the diversity of forms of the male genitalia and other features. He later noted the same thing when revising the genus ( Young 1990), at which time he also described a new species and removed some from the subgenus. Miller (2001) discarded the Desmopachria   subgenera, including Pachriostrix   , and instead recognized this group of species as the D. striola   species-group. The group remains problematic. Several species, including the new species described herein and D. striola   , have seemingly similar male genitalia with features as described under the diagnosis above, whereas others (specifically Desmopachria amyae Miller   , Desmopachria chei Miller   , and Desmopachria fossulata Zimmermann   ) have rather different male genitalia but remain included because of the sutural stria on the elytron ( Fig. 1 View Figs ). Desmopachria amyae   has genitalia similar to those of species in the D. portmanni   species-group, especially Desmopachria duodentata Braga and Ferreira Jr.   Desmopachria chei   has male genitalia more similar to that of Desmopachria rex Gustafson and Miller   and Desmopachria varians Wehncke   than to other species in the D. striola   species-group. It certainly seems possible that the sutural stria is an unreliable character as an indicator of monophyly, though such a dispositive evaluation will require a larger phylogenetic analysis of the group.

Young (1980) included D. fossulata   in Pachriostrix   and later included an image of the genitalia of the species based apparently on a drawing from J. Balfour-Browne ( Young 1990); inexplicably he did not key it or address the species further in that revision. The genitalia ( Fig. 18 View Figs ) are rather different from those of other D. striola   species-group members, and it is not clear that it comports well with the definition of the group.