Morphometric tools to solve species complexes: The case of Rhagovelia angustipes (Hemiptera: Veliidae).

The riffle bugs of the Rhagovelia angustipes complex have presented problems in taxonomy due to high intra-specific variability. Here we identified variation in the complex with morphometric techniques. We analyzed variation of the characters and performed a phylogenetic analysis of a combined matrix of linear measurements, geometric configurations, and discrete characters. We found that characters such as head length, metanotum length, femur width, and the evaluated shape of four characters (head, abdomen, fore tibia, hind femur) were important for the delimitation of species. In particular, we identified the metanotum length as a character that had not been previously considered in the taxonomy of the complex. The phylogenetic reconstruction allowed us to recover some relationships established for the taxonomy of the complex for the salina group, except for the species R. colombiana that was closer to R. calceola and R. calopa. This may be due to a similar natural history, since they share areas of distribution, while the R. bisignata and R. hambletoni groups could not be recovered, showing their low morphological support. In general, the geometric morphometric characters showed high levels of homology, with the head and the anterior tibia being the ones that had the best performance in the tree. Finally, the use of morphometric tools proved to be a powerful input for the taxonomic resolution of species complexes that have problems in their delimitation.

Revision of the emRhagovelia/em emangustipes/em complex (Insecta: Hemiptera: Veliidae) from Colombia.

Water striders of the genus Rhagovelia Mayr, 1865 (Insecta: Hemiptera: Veliidae) have colonized the water surface mainly in lotic freshwater systems, but also in coastal marine environments. They are characterized by the swimming fan in the distal tarsomere of the middle leg that allows them to quickly maneuver. In the Americas, it was subdivided into four monophyletic complexes (angustipes, collaris, obesa and robusta), one paraphyletic grade (abrupta), each with several groups of species, and one additional group (varipes). However, the taxonomy of this genus still has inconsistencies due to its morphological complexity and to the misinterpretation of characters. For this reason, we present a revision of the species of the angustipes complex occurring in Colombia. Material deposited in nine biological collections was examined, including several types. A total of 3,674 specimens  were studied, belonging to 26 valid species, of which R. boyacensis sp. nov., R. graziae sp. nov. and R. molanoi sp. nov., are described as new; and R. angustipes Uhler, 1894 is recorded from the country for the first time. Furthermore, eleven species are redescribed and twelve are considered synonyms. Finally, a key to the species of the angustipes complex occurring in Colombia is presented, as well as updated distribution maps.

Descriptions, records, and key to the Hydrometra Latreille, 1796 (Hemiptera: Heteroptera: Hydrometridae) from Colombia.

Hydrometra colombiana Martínez and Galindo-Malagón, sp. nov., H. tayrona Martínez and Galindo-Malagón, sp. nov., and H. quimbaya Martínez and Galindo-Malagón, sp. nov. are described and compared with congeners. Furthermore, the female of H. williamsi Hungerford Evans, 1934 and the male of H. adnexa Hungerford Evans, 1934 are described. New records from Colombia and a key to the species of Hydrometra Latreille, 1796 recorded from the country are presented.