New paper!

Pavan M.G. et al.: "Phenotypic convergence in Chagas disease vectors: Rhodnius neglectus from Copernicia prunifera palms may express the typical Rhodnius nasutus color phenotype".

Background
Selection for camouflage coloration can lead to phenotypic convergence when closely-related taxa adapt to microhabitats with similar substrate color. Such convergence can, in turn, complicate species diagnosis - an issue of practical relevance when human-disease vectors are involved. Here, we present evidence suggesting that the Chagas disease vectors Rhodnius neglectus and R. nasutus may express similar, substrate-matching color phenotypes when they occupy Copernicia prunifera palms - the primary habitat of R. nasutus in northeastern Brazil.
Methods
We studied triatomines from C. prunifera sampled across the semiarid Caatinga and the Caatinga-Cerrado savanna transition, comparing them with specimens from core-Cerrado Mauritia flexuosa palms. Triatomines were identified by phenotype, then genotyped using mitochondrial cytb and nuclear rDNA ITS2 clone-sequences.
Results
Adult-specimen color patterns distinguished core-Cerrado dark brown (typical) R. neglectus from core-Caatinga light brown (typical) R. nasutus, but were dubious in bugs caught in C. prunifera from the Caatinga-Cerrado transition and parts of the central-western Caatinga. Bayesian cytb genealogies placed dubious-phenotype specimens resembling typical R. nasutus in a sub-clade sister to typical R. neglectus from M. flexuosa - with ~2% mean cytb divergence between sub-clades. ITS2 genealogies recovered R. neglectus and R. nasutus as paraphyletic; however, a multispecies-coalescent analysis suggested that, after accounting for incomplete lineage sorting, dubious-phenotype bugs from C. prunifera cluster with typical R. neglectus.
Conclusions
Rhodnius neglectus dwelling in C. prunifera palms can be chromatically similar to typical, light brown R. nasutus. Mitochondrial cytb sequence analyses helped address the taxonomic uncertainty brought about by this apparent phenotypic convergence. ITS2 results were less clear-cut, with multispecies-coalescent analysis results suggestive of incomplete lineage sorting. Taken together, our results raise the possibility that the atypical, light brown hue of R. neglectus specimens inhabiting C. prunifera may stem from predator-driven natural selection favoring camouflage phenotypes that better match the palm-crown substrate color. These findings contribute to our understanding of color variation in triatomines and call into question the widespread use of overall body color as a key phenotypic character in the taxonomy of these medically important insects.

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New paper!

Monferran M.D., Davranoglou L.-R., Peñalver E.: "Evolutionary insights from a rare male palm bug (Hemiptera: Thaumastocoridae) in Cretaceous amber".

We report the earliest occurrence of the hemipteran family Thaumastocoridae, a Gondwana relict lineage with representatives notorious for the damage they cause to palm crops. The new taxon, Popovocoris punctatus nov. gen. et sp., is based on a unique male specimen exquisitely preserved in Cretaceous Burmese amber and exhibits a dorsoventrally flattened body with fine punctate sculpturing, four-segmented antennae, areolate hemelytra, and distinctive forewings with a dull-white membrane lacking visible venation. By undertaking a morphology-based cladistic analysis, this specimen is placed within Cimicomorpha, specifically within the extant family Thaumastocoridae, and with high certainty in the subfamily Thaumastocorinae, based on key features such as asymmetrical male genitalia. This discovery indicates that the evolution of asymmetrical genitalia in thaumastocorids dates to at least since the early Late Cretaceous. The affinity of this specimen with Thaumastocorinae, predominantly distributed in the Southern Hemisphere (particularly Australia and southern India), provides compelling evidence for a Gondwanan origin of the subfamily. Furthermore, this finding supports the hypothesis of Gondwanan connections for certain Burmese amber taxa, contributing to our understanding of Cretaceous palaeobiogeography and the evolutionary history of this enigmatic hemipteran family, while highlighting the unusually low representation of Cimicomorpha in Cretaceous ambers.

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New paper!

Drosdosky E.V. et al.: "List of Ranatra Species (Heteroptera: Nepomorpha) from the tributaries of the Xingu River in the Brazilian Amazon".

Areas of endemism are geographic units characterized by unique biological diversity and evolutionary histories, enabling the formulation of hypotheses about the processes shaping regional ecosystems. Aquatic insects are essential components of freshwater environments, and the genus Ranatra Fabricius, 1790 is commonly found in slow-flowing streams rich in leaf litter and submerged roots. Known as “water scorpions”, 35 species have been reported across Brazil to date. Despite growing research efforts, substantial gaps remain regarding the diversity of these insects, particularly in terms of species identity (Linnean shortfall) and distribution (Wallacean shortfall). In this study, we present a species list of Ranatra Fabricius, 1790 from streams of the Xingu Basin, Pará State, a region located within the Tapajós and Xingu Areas of Endemism in the Brazilian Amazon. We sampled 165 individuals belonging to 13 species, including three new distributional records for the state of Pará, R. brasiliensis De Carlo, 1946, R. doesburgi De Carlo, 1963, and R. rabida White, 1879. Our findings emphasize the importance of expanding research and monitoring efforts in freshwater systems, particularly in highly diverse regions increasingly threatened by anthropogenic pressures and climate change, such as those of the Amazon biome.

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