RESUMO
Paedomorphosis is a heterochronic syndrome in which adult individuals display features of their immature forms. In beetles, this phenomenon occurs widely in the superfamily Elateroidea, including the net-winged beetles (Lycidae), and, due to the usual flightlessness of paedomorphic females, it is hypothesized to cause speciation rates higher than in non-paedomorphic lineages. However, some fossils of paedomorphic lycids do not support this with palaeobiological data. Discovery of new Lycidae fossils attributed to the West Indian extant paedomorphic genus Cessator Kazantsev in the Dominican amber also suggests morphological stasis within this genus in the Greater Antilles. We describe Cessator anachronicus Ferreira and Ivie, sp. nov. based on adult males, as well as the first ever recorded fossil net-winged beetle larva of the same genus. We propose that the relatively young age of the studied fossils combined with the stable conditions in the forest floor of the Greater Antilles through the last tens of million years could explain the exceptionally conserved morphology in the net-winged beetles affected by the paedomorphic syndrome.
Assuntos
Âmbar , Besouros , Animais , Besouros/anatomia & histologia , República Dominicana , Feminino , Florestas , Fósseis , MasculinoRESUMO
Cleicosta, a new genus of Phengodidae containing two new species, C. equatoreana sp. nov., and C. monaguense sp. nov., are described. Additionally, a new combination for Cenophengus breviplumatusWittmer, 1976 is included. Cleicosta gen. nov., is the thirty-eighth genus assigned to the beetle family Phengodidae in the new world and is also the most morphologically similar to Cenophengus LeConte, 1881. Both genera exhibit clearly separated tentorial pits, vertical frons and simple tarsomeres. In Cleicosta gen. nov., however, the antennal rami are 1.5 times longer than the corresponding antennomere, the pronotum is subquadrate and the elytra are short, reaching the first or second abdominal segment. In addition, it presents an aedeagus with lateral lobes slender, parallel exteriorly, narrowed medially to toothless apex.
Assuntos
Animais , Besouros/anatomia & histologia , Besouros/classificação , Biodiversidade , Classificação , District of Columbia , Montana , MéxicoRESUMO
Cleicosta, a new genus of Phengodidae containing two new species, C. equatoreana sp. nov., and C. monaguense sp. nov., are described. Additionally, a new combination for Cenophengus breviplumatusWittmer, 1976 is included. Cleicosta gen. nov., is the thirty-eighth genus assigned to the beetle family Phengodidae in the new world and is also the most morphologically similar to Cenophengus LeConte, 1881. Both genera exhibit clearly separated tentorial pits, vertical frons and simple tarsomeres. In Cleicosta gen. nov., however, the antennal rami are 1.5 times longer than the corresponding antennomere, the pronotum is subquadrate and the elytra are short, reaching the first or second abdominal segment. In addition, it presents an aedeagus with lateral lobes slender, parallel exteriorly, narrowed medially to toothless apex.(AU)
Assuntos
Animais , Besouros/anatomia & histologia , Besouros/classificação , Biodiversidade , Classificação , México , Montana , District of ColumbiaRESUMO
Abstract Cleicosta, a new genus of Phengodidae containing two new species, C. equatoreana sp. nov., and C. monaguense sp. nov., are described. Additionally, a new combination for Cenophengus breviplumatusWittmer, 1976 is included. Cleicosta gen. nov., is the thirty-eighth genus assigned to the beetle family Phengodidae in the new world and is also the most morphologically similar to Cenophengus LeConte, 1881. Both genera exhibit clearly separated tentorial pits, vertical frons and simple tarsomeres. In Cleicosta gen. nov., however, the antennal rami are 1.5 times longer than the corresponding antennomere, the pronotum is subquadrate and the elytra are short, reaching the first or second abdominal segment. In addition, it presents an aedeagus with lateral lobes slender, parallel exteriorly, narrowed medially to toothless apex.
RESUMO
The impact of ash deposition levels on canopy arthropods was studied on the West Indian island of Montserrat, the site of an ongoing volcanic eruption since 1995. Many of the island's natural habitats have been buried by volcanic debris, and remaining forests regularly receive volcanic ash deposition. To test the effect of ash on canopy arthropods, four study sites were sampled over a 15-mo period. Arthropod samples were obtained using canopy fogging, and ash samples were taken from leaf surfaces. Volcanic ash has had a significant negative impact on canopy arthropod populations, but the decline is not shared equally by all taxa present, and total population variation is within the variance attributed to other aboitic and biotic factors. The affected populations do not differ greatly from those of the neighboring island of St. Kitts, which has not been subject to recent volcanic activity. This indicates that observed effects on Montserrat's arthropod fauna have a short-term acute response to recent ash deposition rather than a chronic depression caused by repeated exposure to ash over the last decade.