Bioacoustics of Troglorhopalurus

REMARKS: Troglorhopalurus was originally monotypic, created to accommodate T. translucidus . In comparing Troglorhopalurus with Rhopalurus , Lourenço et al. (2004: 1153 , 1156) noted “all modifications presented by the new troglobitic scorpion are the result of adaptation to a cave dwelling life,” prompting Prendini et al. (2009) to suggest that Troglorhopalurus might be a junior synonym of Rhopalurus . Rhopalurus lacrau had earlier been described from caves belonging to the same subterranean formation in Brazil and, in the description of Troglorhopalurus , Lourenço et al. (2004) suggested the relationship between these taxa should be investigated using molecular data. Gallão and Bichuette (2016) subsequently identified four morphological characters shared by R. lacrau and T. translucidus , in addition to their troglomorphic habitus (metasomal carination, pectinal tooth count, pectinal peg sensillar shape, and the absence of a pecten-sternite stridulatory apparatus). A close association between the two species was independently verified in the cytogenetic study of Ubinski et al. (2016) which identified a diploid chromosome number of 2n = 20 for R. lacrau and 2n = 20–22 for T. translucidus ( table 2 ). Accordingly, the consistent placement of R. lacrau sister to T. translucidus in the analyses of Esposito et al. (in review) is rather predictable, and justifies the transfer of R. lacrau to Troglorhopalurus and the following new combination: Troglorhopalurus lacrau ( Lourenço and Pinto-da-Rocha 1997 ), comb. nov. (fig. 13).

DIAGNOSIS: Troglorhopalurus differs from Heteroctenus , Jaguajir , gen. nov. , Physoctonus , and Rhopalurus by the proximal dentate margins of the chela fixed and movable fingers of the adult male that are linear, with no gap evident between them, when closed; from Heteroctenus , Jaguajir , and Rhopalurus by the absence of a pecten-sternite stridulatory organ; from Ischnotelson , gen. nov. , and Rhopalurus by the separate (unfused) central lateral and posterior central submedian carinae of the carapace; from Heteroctenus by the presence of two lateral depressions in the male pectinal plate, and a subaculear tubercle on the telson; from Ischnotelson by the separate (unfused) lateral ocular and central lateral carinae of the carapace and the telson vesicle not being laterally compressed; from Jaguajir by the separate (unfused) lateral ocular and anterior central submedian carinae of the carapace; from Physoctonus by the larger size (35–40 mm), the more distinct carapacial carinae, the setose proximal dorsal fulcra of the pectines, the bifurcate prolateral pedal spur of leg I, and the oblique subrows of primary denticles on the pedipalp chela fingers flanked closely by pro- and retrolateral accessory (supernumerary) denticles; from Rhopalurus by the slender metasoma, not increasing in width posteriorly; and from Centruroides by the obsolete retromedian carina on the pedipalp chela manus, and the well-separated dorsointernal and proventral carinae of the pedipalp patella.