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As with all spiders, tarantulas spin silk from specialized structures in the abdomen called spinnerets, which are key features unique to the group. Recently Gorb et al. reported that the zebra tarantula Aphonopelma seemanni also secretes silk from its feet, which might improve its ability to climb on vertical surfaces. Here we show that when the spinnerets are experimentally sealed, the zebra tarantula cannot secrete silk or similar threads, disagreeing with previous reports by Gorb et al.. Additional evidence also disagrees with leg secretion of silk.

The genus Liolaemus is one of the most ecologically diverse and species-rich genera of lizards worldwide. It currently includes more than 250 recognized species, which have been subject to many ecological and evolutionary studies. Nevertheless, Liolaemus lizards have a complex taxonomic history, mainly due to the incongruence between morphological and genetic data, incomplete taxon sampling, incomplete lineage sorting and hybridization. In addition, as many species have restricted and remote distributions, this has hampered their examination and inclusion in molecular systematic studies. The aims of this study are to infer a robust phylogeny for a subsample of lizards representing the Chilean clade (subgenus Liolaemus sensu stricto), and to test the monophyly of several of the major species groups. We use a phylogenomic approach, targeting 541 ultra-conserved elements (UCEs) and 44 protein-coding genes for 16 taxa. We conduct a comparison of phylogenetic analyses using maximum-likelihood and several species tree inference methods. The UCEs provide stronger support for phylogenetic relationships compared to the protein-coding genes; however, the UCEs outnumber the protein-coding genes by 10-fold. On average, the protein-coding genes contain over twice the number of informative sites. Based on our phylogenomic analyses, all the groups sampled are polyphyletic. Liolaemus tenuis tenuis is difficult to place in the phylogeny, because only a few loci (nine) were recovered for this species. Topologies or support values did not change dramatically upon exclusion of L. t. tenuis from analyses, suggesting that missing data did not had a significant impact on phylogenetic inference in this data set. The phylogenomic analyses provide strong support for sister group relationships between L. fuscus, L. monticola, L. nigroviridis and L. nitidus, and L. platei and L. velosoi. Despite our limited taxon sampling, we have provided a reliable starting hypothesis for the relationships among many major groups of the Chilean clade of Liolaemus that will help future work aimed at resolving the Liolaemus phylogeny.

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The ability of Grammoslola. moliicoma (Ausserer 1875) spiderlings (Araneae, Theraphosidae) to emerge from the cocoon without the assistance of their mother was tested experimentally. We created two experimental groups with 23 cocoons in each group. In one of the groups we cut the cocoon wall creating an opening; in the other group, the cocoon remained untouched. We found no differences between the groups in either the number or instar composition of the spiderlings that emerged. The spiderlings were able to emerge without the assistance of their mother. The emerging instars in both groups were precocious compared to previous suggestions in the literature.Resumen. Ponemos a prueba experimentalmente la capacidad de Grammostola moliicoma (Ausserer 1875) (Araneae, Theraphosidae) para salir de la ooteca sin asistencia de su madre. Creamos dos grupos experimentales cada uno con 23 ootecas. En uno de los grupos cortamos la pared de la ooteca mientras que el otro permanecio intocado (grupo control). No encontramos diferencias en el mimero de aranitas emergidas ni en los estadios de emergencia entre los grupos. Los hijos pudieron emerger sin la asistencia de su madre. Los estadios en que las aranitas emergieron en ambos grupos fueron levemente mas precoces que lo indicado previamente en la literatura. Se discuten posibles explicaciones para estos resultados.