Beyond the exponential horn: a bush-cricket with ear canals which function as coupled resonators.

Bush-crickets have dual-input, tympanal ears located in the tibia of their forelegs. The sound will first of all reach the external sides of the tympana, before arriving at the internal sides through the bush-cricket's ear canal, the acoustic trachea (AT), with a phase lapse and pressure gain. It has been shown that for many bush-crickets, the AT has an exponential horn-shaped morphology and function, producing a significant pressure gain above a certain cut-off frequency. However, the underlying mechanism of different AT designs remains elusive. In this study, we demonstrate that the AT of the duetting Phaneropterinae bush-cricket Pterodichopetala cieloi function as coupled resonators, producing sound pressure gains at the sex-specific conspecific calling song frequency, and attenuating the remainder-a functioning mechanism significantly different from an exponential horn. Furthermore, it is demonstrated that despite the sexual dimorphism between the P. cieloi AT, both male and female AT have a similar biophysical mechanism. The analysis was carried out using an interdisciplinary approach, where micro-computed tomography was used for the morphological properties of the P. cieloi AT, and a finite-element analysis was applied on the precise tracheal geometry to further justify the experimental results and to go beyond experimental limitations.

Cryptic new species of Nesoecia Scudder, 1893 (Orthoptera: Tettigoniidae; Pseudophyllinae) from northeastern, Mexico.

Nesoecia Scudder, 1893 is a neotropical genus of true katydids (Pseudophyllinae) comprising four species: N. brasiliensis (Bruner, 1915) from Brazil (Bahia), N. cooksonii (Butler, 1877) from Ecuador (Galápagos, Floreana Island), and two species from southern Mexico: N. insignis (Hebard, 1932) from Yucatán (Temax and Chichen-Itza), and N. nigrispina (Stål, 1873) reported also from Yucatán and the State of Tabasco (Teapa). Members of this genus are large and attractive insects, nonetheless, they have been poorly studied since they are not abundant or commonly collected. This paper describes four new species of Nesoecia from the Huasteca Region in northeastern México: N. huichihuayan n. sp., N. potoniya n. sp., N. insolita n. sp., and N. constricta n. sp. Taxa delimitation is based on morphological diagnostic characters and parameters of the acoustic signal. Information on distribution, habitat, and behavior is provided. [urn:lsid:zoobank.org:act:B932F2DC-97F4-4751-A6F7-0869318364FA].

New species of the genus Caloxiphus Saussure amp; Pictet, 1898 (Orthoptera: Tettigoniidae) from the Huasteca Region, Hidalgo, Mexico.

Two new species of the genus Caloxiphus Saussure Pictet, 1898 (Pseudophyllinae) are described: C. chapulhuacan n. sp., and C. cuicani n. sp., both endemic to the Huasteca Region, State of Hidalgo, Mexico. These two new taxa show morphological affinities to C. championi Saussure Pictet, 1898. However, they may be separated from the latter species on basis of external and internal (genitalia) morphological characters that are provided and illustrated. Acoustic signals for C. cuicani n. sp., and information on distribution for both new taxa are given.

Molecular systematics of the Dichopetala genus group (Orthoptera: Phaneropteridae)

Introducción: El grupo de géneros Dichopetala se propuso recientemente después de una revisión del género Dichopetala Brunner von Wattenwyl, 1878. Actualmente, el grupo consta de ocho géneros y 44 especies distribuidas desde el sur de los Estados Unidos hasta el sur de México. Este acuerdo genérico, se basó únicamente en evidencia morfológica y se acompañó por discusiones sobre nuevos géneros erigidos, para los cuales no se probó su monofilia. Objetivo: Evaluar las relaciones filogenéticas entre especies representativas de los ocho géneros del grupo Dichopetala. Métodos: Generamos secuencias de ADN para un gen mitocondrial (Citocromo oxidasa I: COI) y dos marcadores de genes nucleares (28S, Histona III: H3), e incluimos especies de otros géneros de Phaneropterinae para probar la monofilia del grupo en estudio. Utilizamos modelos evolutivos bayesianos y de máxima verosimilitud. Resultados: Se respalda la monofilia del grupo Dichopetala y la monofilia de los géneros Dichopetala, Obolopteryx, Planipollex, Mactruchus y Rhabdocerca. Además, los géneros Acanthorintes y Pterodichopetala como parafiléticos. Los marcadores mitocondriales también sugieren que los géneros Rhabdocerca y Acanthorintes ampliamente distribuidos, pueden en realidad contener varias especies no vistas previamente. Conclusión: Se proporciona la primera contribución a la filogenia del grupo de Dichopetala y una definición filogenética y morfológica más robusta de algunos de los géneros involucrados.

Introduction: The Dichopetala genus group was proposed recently after revision of the genus Dichopetala Brunner von Wattenwyl, 1878. Currently, the group consists of eight genera and 44 species distributed from Southern United States to Southern Mexico. This generic arrangement was based solely on morphological evidence, and was accompanied by discussions on new erected genera, for which their monophyly was not tested. Objective: To assess the phylogenetic relationships among representative species of the eight genera of the Dichopetala group. Methods: We generated DNA sequences for one mitochondrial (Cytochrome oxidase I: COI) and two nuclear (28S, Histone III: H3) gene markers, and included species of other Phaneropterinae genera to test the monophyly of the ingroup; Bayesian and maximum likelihood evolutionary models were used. Results: The monophyly of the Dichopetala group and the monophyly of genera Dichopetala, Obolopteryx, Planipollex, Mactruchus and Rhabdocerca is supported. In addition, Acanthorintes and Pterodichopetala were recovered as paraphyletic. The mitochondrial markers also suggest that the widely distributed genera Rhabdocerca and Acanthorintes may actually contain various overlooked species. Conclusions: The first contribution on the Phylogeny of the Dichopetala group, and a more robust phylogenetic and morphological definition of some of the genera involved are provided.

Additional new species of the genus Obolopteryx Cohn et al. 2014 (Ensifera: Tettigoniidae) from Northeastern Mexico.

The present contribution describes five new species of Phaneropterinae from Northeastern Mexico: Obolopteryx eurycerca n. sp., Barrientos-Lozano & Rocha-Sánchez, O. nigra n. sp., Barrientos-Lozano & Rocha-Sánchez, O. tamaholipana n. sp., Barrientos-Lozano & Rocha-Sánchez, O. huastecana n. sp., Barrientos-Lozano & Rocha-Sánchez, and O. tanchipae n. sp., Barrientos-Lozano & Rocha-Sánchez. Diagnostic characters are illustrated and information on distribution and ecology provided. Polymorphism and geographic variation of the genus Obolopteryx Cohn et al. 2014 are discussed.

A new species of the genus Obolopteryx Cohn et al. 2014 and a conspecific gynandromorph (Ensifera: Tettigoniidae: Phaneropterinae).

Obolopteryx truncoangulata n. sp., Barrientos-Lozano & Rocha-Sánchez, and a field collected conspecific gynandromorph are described, both from the northern Mexico's Highland. O. truncoangulata n. sp., may be separated from congeneric O. brevihastata based on morphological characters. The male's pronotum is more constricted mesally, and the tegmina are shorter. The disto-dorsal abdominal tergites sub-triangular projection broadly bilobated. Cerci broader proximally, and thumb and shaft more robust and shorter; subgenital plate deep "U" shape emarginated distally, lateral angles excised about mid portion. In females, tegmina, ovipositor, subgenital plate and basal sclerites are of different shape than analogous structures in O. brevihastata. Information on geographic distribution and ecology is provided.

Montane and coastal species diversification in the economically important Mexican grasshopper genus Sphenarium (Orthoptera: Pyrgomorphidae).

The genus Sphenarium (Pyrgomorphidae) is a small group of grasshoppers endemic to México and Guatemala that are economically and culturally important both as a food source and as agricultural pests. However, its taxonomy has been largely neglected mainly due to its conserved interspecific external morphology and the considerable intraspecific variation in colour pattern of some taxa. Here we examined morphological as well as mitochondrial and nuclear DNA sequence data to assess the species boundaries and evolutionary history in Sphenarium. Our morphological identification and DNA sequence-based species delimitation, carried out with three different approaches (DNA barcoding, general mixed Yule-coalescent model, Bayesian species delimitation), all recovered a higher number of putative species of Sphenarium than previously recognised. We unambiguously delimit seven species, and between five and ten additional species depending on the data/method analysed. Phylogenetic relationships within the genus strongly support two main clades, one exclusively montane, the other coastal. Divergence time estimates suggest late Miocene to Pliocene ages for the origin and most of the early diversification events in the genus, which were probably influenced by the formation of the Trans-Mexican Volcanic Belt. A series of Pleistocene events could have led to the current species diversification in both montane and coastal regions. This study not only reveals an overlooked species richness for the most popular edible insect in Mexico, but also highlights the influence of the dynamic geological and climatic history of the region in shaping its current diversity.

Two new species of Melanoplus Stål, 1873 (Orthoptera: Acrididae: Melanoplinae) from northeastern Mexico.

Two new species of the genus Melanoplus Stål 1873 are described. M. trachodes n. sp., and M. parvus n. sp., both of which are endemic to the cool-temperate mountains of the Eastern Sierra Madre (ESM) in northeastern Mexico. Their habitat represents a transition zone between the ESM and the semiarid High Plateau Biogeographic provinces. This transition zone is characterized by an elevation range from 1,900 to 3,400 m and unique ecological conditions, which give rise to a considerable number of endemisms.