RESUMEN
Geocharis ruiztapiadori Zaballos, 1997 is redescribed, increasing more than double the morphological features used in the genus, that includes a dimorphic character and several autapomorphies. The first specimen outside of the type location is found, with a representative difference in ring sclerite. New structures described open a new way to study the Geocharis morphology and deepen into the relations with other genus of the tribe.
Asunto(s)
Escarabajos , AnimalesRESUMEN
Antlion larvae have a complex tegumentary sensorial equipment. The sensilla and other kinds of larval tegumentary structures have been studied in 29 species of 18 genera within family Myrmeleontidae, all of them with certain degree of psammophilous lifestyle. The adaptations for such lifestyle are probably related to the evolutionary success of this lineage within Neuroptera. We identified eight types of sensory structures, six types of sensilla (excluding typical long bristles) and two other specialized tegumentary structures. Both sensilla and other types of structures that have been observed using scanning electron microscopy show similar patterns in terms of occurrence and density in all the studied species (with few exceptions). The sensilla identified are: coeloconica, placoidea, basiconica, trichodea type I, trichodea type II, and campaniformia. All these sensilla have mechano- or chemosensorial functions. Some regions of the larval body have been studied using SEM for the first time, such as the surface of the food canal, which bears sensilla coeloconica, and the abdominal segment X, that bears three types of sensilla: coeloconica, basiconica, and campaniformia. Sensilla placodea are newly reported on antlion larvae, being present on the mandibular base, pronotum, mentum, and cardum. Also, new locations of sensilla coeloconica (e.g., on rastra) and sensilla campaniformia (e.g., on odontoid processes) are noted. A novel porous texture with chemoreceptor function has been identified in the base of mandibles. A mechanism of dentate-notched surfaces that anchor maxillae and mandible, reinforcing the food canal, is detailed. All these sensorial structures, in addition to ocular tubercles for light caption and their great muscular system, confer to these larvae an extraordinary predation capacity to success hunting and living in such harsh environments.
Asunto(s)
Insectos/anatomía & histología , Sensilos/anatomía & histología , Abdomen/anatomía & histología , Animales , Extremidades/anatomía & histología , Femenino , Insectos/ultraestructura , Larva/anatomía & histología , Larva/ultraestructura , Masculino , Sensilos/ultraestructuraRESUMEN
Typhlocharis is the most diverse eyeless endogean ground beetle genus known to date, with 62 species all endemic to the West Mediterranean region. The lineage is characterized by a conservative and singular body plan within Carabidae that contrasts with a high morphological diversity in many traits. We provide an exhaustive phylogeny of the lineage through the study of 92 morphological characters from all 62 described species and 45 potential new species from 70 additional populations, and the combination of morphological and available molecular data, in the first total evidence phylogenetic approach for a highly diverse endogean lineage. We tracked the evolution of morphological traits over the obtained phylogenies. Results suggest eight morphologically distinct clades, which do not correspond to the species groups proposed formerly. Ancestral state reconstructions and phylogenetic signal analyses of morphological traits revealed that some of the previously key characters to the classification of Typhlocharis, such as the umbilicate series or the apical denticles of elytra, are highly homoplasic, whereas other characters show stronger phylogenetic signal, including structures in the antennae, gula, pronotum and last abdominal ventrite. This evidence supports the split of Typhlocharis into three genera: Lusotyphlus gen. nov.; Typhlocharis Dieck, 1869 and Microcharidius Coiffait, 1969 (revalidated), forming the subtribe Typhlocharina Jeanne, 1973.
RESUMEN
Dispersal is a critical factor determining the spatial scale of speciation, which is constrained by the ecological characteristics and distribution of a species' habitat and the intrinsic traits of species. Endogean taxa are strongly affected by the unique qualities of the below-ground environment and its effect on dispersal, and contrasting reports indicate either high dispersal capabilities favoured by small body size and mediated by passive mechanisms, or low dispersal due to restricted movement and confinement inside the soil. We studied a species-rich endogean ground beetle lineage, Typhlocharina, including three genera and more than 60 species, as a model for the evolutionary biology of dispersal and speciation in the deep soil. A time-calibrated molecular phylogeny generated from >400 individuals was used to delimit candidate species, to study the accumulation of lineages through space and time by species-area-age relationships and to determine the geographical structure of the diversification using the relationship between phylogenetic and geographic distances across the phylogeny. Our results indicated a small spatial scale of speciation in Typhlocharina and low dispersal capacity combined with sporadic long distance, presumably passive dispersal events that fuelled the speciation process. Analysis of lineage growth within Typhlocharina revealed a richness plateau correlated with the range of distribution of lineages, suggesting a long-term species richness equilibrium mediated by density dependence through limits of habitat availability. The interplay of area- and age-dependent processes ruling the lineage diversification in Typhlocharina may serve as a general model for the evolution of high species diversity in endogean mesofauna.
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Escarabajos/clasificación , Ecosistema , Especiación Genética , Animales , Geografía , FilogeniaRESUMEN
Anillini are a tribe of minute, euedaphic ground beetles (Carabidae) characterized by the loss of eyes, loss of wings and high levels of local endemism. Despite their presumed low dispersal, they have a nearly cosmopolitan distribution, including isolated islands such as New Zealand and New Caledonia. We used a time calibrated molecular phylogeny to test, first, if the tribe as currently understood is monophyletic and, second, whether the time of divergence is compatible with an early vicariant diversification after the breakup of Gondwana. We sequenced portions of 6 mitochondrial and 3 nuclear genes for 66 specimens in 17 genera of Anillini plus 39 outgroups. The resulting phylogenetic tree was used to estimate the time of diversification using two independent calibration schemes, by applying molecular rates for the related genus Carabus or by dating the tree with fossil and geological information. Rates of molecular evolution and lineage ages were mostly concordant between both calibration schemes. The monophyly of Anillini was well-supported, and its age was consistent with a Gondwanian origin of the main lineages and an initial diversification at ca. 100Ma representing the split between the eyed Nesamblyops (New Zealand) and the remaining Anillini. The subsequent diversification, including the split of the Nearctic Anillinus and the subsequent splits of Palaearctic lineages, was dated to between 80 and 100Ma and thus was also compatible with a tectonic vicariant origin. On the contrary, the estimated age of the New Caledonian blind Orthotyphlus at ca. 30±20Ma was incompatible with a vicariant origin, suggesting the possibility of trans-oceanic dispersal in these endogean beetles.
Asunto(s)
Escarabajos/clasificación , Animales , Teorema de Bayes , Biodiversidad , Evolución Biológica , Escarabajos/genética , Ciclooxigenasa 1/genética , ADN/química , ADN/aislamiento & purificación , ADN/metabolismo , Mitocondrias/genética , Nueva Caledonia , Nueva Zelanda , Filogenia , Análisis de Secuencia de ADNRESUMEN
The antennal morphology and chaetotaxy were studied in 52 species of the endogean carabid genus Typhlocharis, using scanning electron microscopy and light microscopy. The antennae are composed of 11 antennomeres (scape, pedicel, and nine flagellomeres). We found considerable variation between species in the third antennomere, with short-stem and long-stem forms, and flagellomere morphology, distinguishing two morphs: rounded (subovoid, subspheric and subquadrate, morph 1) and reniform shapes (morph 2). Antennal sensilla are grouped in six types of sensilla trichodea, three types of sensilla basiconica, one type of sensilla coeloconica, and one type of sensilla campaniformia. The distribution of sensilla along the antennomeres is described. The "rings" of trichoid sensilla in the antennomere body are affected by its shape and there is interspecific variation in the pattern of sensilla coeloconica in antennomere 11°, a novelty for the genus. The types of sensilla found in Typhlocharis are compared to those described in other Carabidae and the potential functionality and taxonomic interest of those variable antennal features are discussed. A correlation between the flagellomere morphology and the presence/absence of a stridulatory organ is suggested. The study also allowed comparing the observation of antennal features by SEM and light microscopy.
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Antenas de Artrópodos/anatomía & histología , Escarabajos/anatomía & histología , Escarabajos/clasificación , Sensilos/anatomía & histología , Animales , Antenas de Artrópodos/ultraestructura , Femenino , Masculino , Microscopía Electrónica de Rastreo , Sensilos/ultraestructuraRESUMEN
Tarsal tetramery is a rare condition within Carabidae, only found in some members of the endogean tribe Anillini and some cases of Gehringiini. Reduction of tarsomere numbers is also reported in endogean members of other families (e.g. Curculionidae or Staphylinidae). Recent fieldwork in southwestern Spain provided specimens of three new species of the endogean Anillini Typhlocharis Dieck, 1869: T. baeturica n.sp., T. scrofa n.sp. and T. tetramera n.sp. The new species share extreme body size reduction (less than 1.1 mm), a gula partially fused to the cephalic capsule, with diffuse lateral sutures, and four tarsomeres in all the legs. Tarsal tetramery is recorded for the first time within the genus Typhlocharis and it is contrasted with the described cases in Anillini. Typhlocharis scrofa n.sp. and T. tetramera n.sp. have club-shaped gonocoxites, reminiscent of the unguiform-like morphology observed in T. quadridentata (Coiffait, 1969), supporting the hypothesis of a transitional evolution of the shape of gonocoxites. The structure of the gula is studied within the genus and includes wide, narrow and diffuse morphologies. The implications of these features and data from the new species enable us to propose a reorganization of the systematics of the genus, creating and defining a new group of species, quadridentata group. An identification key for this species group is included. The new species provides more data on syntopic species and abundance rates, brief insights on the ecology of the genus.
Asunto(s)
Escarabajos/anatomía & histología , Escarabajos/clasificación , Animales , Femenino , Masculino , Portugal , España , Especificidad de la EspecieRESUMEN
Two new species of Typhlocharis Dieck, 1869 from the southwest of the Iberian Peninsula included in baetica species group are described: T acutangula n. sp. and T. mixa n. sp. The new species can be easily recognized by the presence of an anterodistal dentiform projection in metatibia (T. acutangula sp.n) and pseudotetramery and a medial tooth in clypeus (T mixta sp.n), features not observed in any other species of the group, but present in quadridentata and gomezi groups respectively. An updated key of baetica group is provided. The large series of T. mixta n. sp. allowed a good study of intraspecific variation, which is detailed and compared within the genus. Implications for the systematics and relations of the baetica group are discussed. Intraspecific variations are grouped in four categories: individual variations in shape, size and proportions, alterations in chaetotaxy, asymmetries, and teratologies or malformations. Finally, implications and problems of intraspecific variability for the systematics of the genus are discussed.