Mauricio García

Larval Morphology of Meruidae (Coleoptera: Adephaga) and Its Phylogenetic Implications

ABSTRACT Meruidae, or comb-clawed cascade beetles, are a recently discovered monotypic family of Adephaga endemic to Venezuela. The larvae of Meruidae are described for the first time, based on material of Meru phyllisae Spangler & Steiner, 2005, collected together with adults in southern Venezuela. External morphological features, including chaetotaxy, are reported for the mature larva and an assessment made of the polarity of larval characters of phylogenetic utility in Adephaga. Larvae of Meruidae possess a mixture of primitive and derived character states, and they are unique within the Adephaga in that here the mandibles are asymmetrical, the respiratory system is comprised of only two pairs of spiracles (= oligopneustic), the claws are pectinate, and the abdominal sternite VIII is prolonged overlapping the abdominal sternite IX. A parsimony analysis based on 18 informative larval characteristics was conducted with the program PAUP*. The most parsimonious trees confirm Meruidae as a relatively basal lineage within the Dytiscoidea. Both Meru Spangler & Steiner and Noteridae are hypothesized to have diverged anterior to Amphizoidae, Aspidytidae, Hygrobiidae, and Dytiscidae.

Ancient associations of aquatic beetles and tank bromeliads in the Neotropical forest canopy

Water reservoirs formed by the leaf axils of bromeliads are a highly derived system for nutrient and water capture that also house a diverse fauna of invertebrate specialists. Here we investigate the origin and specificity of bromeliad-associated insects using Copelatinae diving beetles (Dytiscidae). This group is widely distributed in small water bodies throughout tropical forests, but a subset of species encountered in bromeliad tanks is strictly specialized to this habitat. An extensive molecular phylogenetic analysis of Neotropical Copelatinae places these bromeliadicolous species in at least three clades nested within other Copelatus. One lineage is morphologically distinct, and its origin was estimated to reach back to 12–23 million years ago, comparable to the age of the tank habitat itself. Species of this clade in the Atlantic rainforest of southern Brazil and mountain ranges of northern Venezuela and Trinidad show marked phylogeographical structure with up to 8% mtDNA divergence, possibly indicating allopatric speciation. The other two invasions of bromeliad water tanks are more recent, and haplotype distributions within species are best explained by recent expansion into newly formed habitat. Hence, bromeliad tanks create a second stratum of aquatic freshwater habitat independent of that on the ground but affected by parallel processes of species and population diversification at various temporal scales, possibly reflecting the paleoclimatic history of neotropical forests.

Systematic placement of the recently discovered beetle family Meruidae (Coleoptera: Dytiscoidea) based on molecular data

The family Meruidae has been established recently for the newly discovered species Meru phyllisae Spangler & Steiner, 2005 from Southern Venezuela. These beetles are morphologically highly distinct and at a body length of 0.8 mm represent the perhaps smallest individuals of Adephaga. Here, we use DNA sequence data to place this enigmatic taxon relative to other aquatic groups in this suborder. Meruidae was most closely associated with Noteridae, supporting a previous analysis of morphological structures which had suggested this sister relationship, albeit with weak support. While different alignment strategies did not affect the topology, the precise placement of Meruidae was affected by the choice of tree reconstruction method. Bayesian inference suggests a sister relationship of Meruidae + Noteridae, while parsimony analyses retrieve Meruidae + Notomicrus (a basal noterid genus), which combined are the sister group of all remaining Noteridae. Considering morphological evidence, the former placement appears more plausible.

Tobochares sulcatus, a new genus and species of water scavenger beetle from Amazonas State, Venezuela (Coleoptera: Hydrophilidae: Hydrophilini)

Abstract A remarkable new genus and species of water scavenger beetle, Tobochares sulcatus, is described and illustrated from the rock formation known as El Tobogan de la Selva, in Amazonas State, Venezuela. It is placed in the subtribe Acidocerina of the tribe Hydrophilini. It is characterised by its small size, eight-segmented antennae, nearly glabrous hind femora, and sulcate elytral striae. It is associated with flat, wet rock faces and small rock pools that are covered with or contain fallen leaves.

Revision of the Neotropical water scavenger beetle genus Globulosis García, 2001 (Coleoptera: Hydrophilidae: Acidocerinae)

The Neotropical water scavenger beetle genus Globulosis García, 2001 is revised. Originally described from a single male specimen from southeastern Venezuela, the genus has since been found in localities across the Guiana Shield region and beyond, including Colombia, Suriname, Guyana, and Brazil. The genus is redescribed. Morphological characters and genetic data from the mitochondrial gene COI from ten populations across its range provide support for two distinct species, corresponding loosely to geography. The type species, G. hemisphericus García, is redescribed and newly recorded from Guyana, Suriname, and Brazil (Amazonas, Para). One new species is described, Globulosis flavus sp. n. from southwestern Venezuela (Amazonas, Bolivar). The genus is associated with lotic habitats, and typically found along the margins of small to medium sized streams. High-resolution habitus and aedeagal images and distribution maps for all species are provided.

Molecular phylogeny of the Hydroscaphidae (Coleoptera: Myxophaga) with description of a remarkable new lineage from the Guiana Shield

The phylogeny of the aquatic beetle family Hydroscaphidae is inferred from one mitochondrial (COI) and five nuclear (18S, 28S, wingless, arginine kinase and CAD) genes. Bayesian, maximum likelihood and maximum parsimony analyses were conducted on a combined dataset that included representatives from all three described hydroscaphid genera, three new species of the family of uncertain placement, and representatives from the myxophagan families Sphaeriusidae, Torridincolidae and Lepiceridae. All analyses strongly supported a set of nearly identical trees in which (i) the monophyly of Hydroscaphidae and all its constituent genera is affirmed, (ii) the nearly cosmopolitan genus Hydroscapha is sister to the remaining and exclusively Neotropical genera, and (iii) the new, morphologically aberrant taxa from the Guiana Shield form a monophylum separate from any described genus. Here, we review each genus of the family including the description of Confossa Short, Joly, García & Maddison gen.n. to accommodate three new species: C. sculptura sp.n., C. falcata sp.n. and C. minima sp.n. The new genus possesses a remarkable perforated abdominal surface that we hypothesize serves as a respiratory plastron. We also present a key to the genera and a catalogue of species of the family.

A new genus of egg case-carrying water scavenger beetle from the Guiana Shield (Coleoptera: Hydrophilidae: Acidocerinae)

Radicitus gen. n. is described to accommodate three new species of water scavenger beetles from the Guiana Shield region of South America: R. ayacucho sp. n. (Venezuela), R. granitum sp. n. (Venezuela), and R. surinamensis sp. n. (Suriname). The genus is placed in the subfamily Acidocerinae, and likely shares an affinity with the genus Helochares Mulsant and its relatives. It is characterized by its convex body form, short maxillary palps, partially glabrous hind femora, and complete fifth abdominal ventrite. All collections of the new genus were made from root mats and debris from seepages over rock outcrops or, rarely, root mats from streams. Individual females of all three species were observed to adhere their egg case to the venter of the abdomen.

Are noterids specialised meruids (Coleoptera, Adephaga)? A reply to Dressler et al.

1Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS, U.S.A., 2Division of Entomology, Biodiversity Institute, University of Kansas, Lawrence, KS, U.S.A., 3Department of Biology, Laurentian University, Sudbury, Ontario, Canada, 4Centro de Investigacions Biológicas, Universidad del Zulia, Maracaibo, Estado Zulia, Venezuela and 5Museo del Instituto de Zoologia Agricola, Universidad Central de Venezuela, Maracay, Estado Aragua, Venezuela

New species and new records of the hygropetric water beetle genus Oocyclus Sharp from South America (Coleoptera: Hydrophilidae)

Three new species of Oocyclus Sharp, 1882 are described from tropical South America: O. maluz sp. n. (Venezuela), O. miza sp. n. (Venezuela), and O. brunneus sp. n. (Bolivia). New distributional records are provided for O. andinus Short & García, O. coromoto Short & García (newly recorded from Suriname), O. floccus Short & García (newly recorded from Guyana and Suriname), O. iguazu (Oliva), O. meridensis Short & García, O. petra Short & García (newly recorded from Guyana and Suriname), O. trio Short & Kadosoe (newly recorded from Guyana), O. trujillo Short & García, and O. yubai Clarkson & Short (newly recorded from Paraguay). Updates to the keys of the Brazilian and Venezuelan Oocyclus species are provided.

DISCOVERY OF THE SKIFF BEETLE GENUS YARA REICHARDT AND HINTON (COLEOPTERA :M YXOPHAGA :H YDROSCAPHIDAE) IN VENEZUELA, WITH DESCRIPTION OF A NEW SPECIES

ABSTRACT The Neotropical skiff beetle genus Yara Reichardt and Hinton is recorded from Venezuela for the first time, marking the first discovery of the genus since its original description in 1976. The Venezuelan species, Yara maculata Short, Joly, and Garcia, new species, is described and illustrated, bringing the total number of species in the genus to three. It is currently known from several localities along the northwestern edge of the Guiana Shield. The presence of a mat of recumbent setae on tergite IV, often considered diagnostic for the family, is found to be absent in Yara. A key to the three species is provided as well as observations on the habitat and seasonality of the new species.