Species of the cobweb spider genus Anelosimus range from solitary to subsocial to social, and sociality has evolved repeatedly within the genus. Thus, this genus allows studies of the traits that play a role in social evolution. However, taxonomic knowledge of Anelosimus is geographically narrow and nearly all sociobiological studies have been done in the Americas. Only one behaviourally unknown species has been described from all of Australasia. Here, I describe seven new Anelosimus from Papua New Guinea (Anelosimus potmosbi, sp. nov., Anelosimus pomio, sp. nov., Anelosimus eidur, sp. nov. and Anelosimus luckyi, sp. nov.), Bali (Anelosimus bali, sp. nov.), Australia (Anelosimus pratchetti, sp. nov.) and an unknown locality (Anelosimus terraincognita, sp. nov.), ranging from solitary to subsocial. A phylogenetic analysis supports the inclusion of these species in Anelosimus, and suggests that solitary Papuan species represent a second reversal from subsocial behaviour. Both solitary species inhabit the beachfront, a habitat that appears not to be conducive to social behaviour in spiders. Subsocial species, as in other parts of the world, are found in montane tropical forests of Papua New Guinea, and at relatively high latitudes in Australia. Thus, a global ecological pattern of sociality in Anelosimus is emerging as taxonomic, phylogenetic and ethological knowledge extends beyond the Americas.

Morphological characters of well-established taxonomic utility are infrequently examined for their relative phylogenetic consistency. Second only to characters of reproductive anatomy, jaw morphology and dentition commonly are employed as diagnostic characters for hirudiniform leeches, yet these features are highly variable across the group. Patterns of change were investigated for number of jaws and number of denticles per jaw in a phylogenetic context across 17 hirudiniform leeches representing three families. Phylogeny reconstruction employed 16 morphological characters, as well as two nuclear and two mitochondrial loci, and was evaluated with parsimony and likelihood. Rather than constrain the ancestral number of denticles to extant states, this meristic was optimised with squared-change parsimony. The degree to which dentition patterns were explained by phylogenetic relationships was assessed against a null distribution defined by permutation of extant states across terminals. Dentition was found to be non-randomly explained by phylogeny and, thus, corroborative of relationships among hirudiniform leeches as well as of the uniqueness of a new species of Oxyptychus described here from the Peruvian Amazon.

The origin and radiation of the major metazoan groups can be elucidated by phylogenomic studies, but morphological evolution must be inferred from embryology and morphology of living organisms. According to the trochaea theory, protostomes are derived from a holoplanktonic gastraea with a circumblastoporal ring of downstream-collecting compound cilia (archaeotroch) and a nervous system comprising an apical ganglion and a circumblastoporal nerve ring. The pelago-benthic life cycle evolved through the addition of a benthic adult stage, with lateral blastopore closure creating a tube-shaped gut. The archaeotroch became differentiated as prototroch, metatroch and telotroch in the (trochophora) larva, but was lost in the adult. The apical ganglion was lost in the adult, as in all neuralians. Paired cerebral ganglia developed from the first micromere quartet. The circumblastoporal nerve became differentiated into a pair of ventral nerve cords with loops around mouth (the anterior part of the blastopore) and anus. Almost all new information about morphology and embryology fits the trochaea theory. The predicted presence of a perioral loop of the blastoporal nerve ring has now been demonstrated in two annelids. Alternative ‘intercalation theories’ propose that planktotrophic larvae evolved many times from direct-developing ancestors, but this finds no support from considerations of adaptation.

The Australian endemic ant-mimetic seed bug genus Daerlac is revised. This paper provides a redescription of the genus Daerlac and four species: D. apicalis, D. cephalotes, D. nigricans and D. picturatus. Daerlac tricolor is synonomised with D. cephalotes. A taxonomic key to species is provided. Known distributions of D. apicalis, D. nigricans and D. picturatus are each extended beyond previously known ranges. Daerlac species are found predominantly in temperate open forest and woodlands in association with ants and eucalypts. All species are broadly distributed and there is a high degree of overlap in distributions. They are seed predators found on the ground, in leaf litter, under bark or on trunks of eucalypts, and putatively forage on post-dispersed seeds. Cladistic analysis of morphological characters finds that the four species of Daerlac form two well-supported sister-groups (D. apicalis   D. picturatus, and D. cephalotes   D. nigricans). A discussion of the distribution, biology and myrmecomorphy of the genus is provided, and the tribal placement of Daerlac and its relationship to Laryngodus are discussed.

The genus Lachnopus Schoenherr (Coleoptera : Curculionidae : Entiminae : Geonemini Gistel), with 66 species described to date, is the largest and most widespread entimine weevil genus in the Caribbean region. The monophyly and internal phylogenetic composition of Lachnopus are tested, using a cladistic analysis of 61 adult morphological characters of 31 ingroup species and five outgroup taxa representing the genera Diaprepes Schoenherr, Exophthalmus Schoenherr, Pachnaeus Schoenherr (all Eustylini), Ischionoplus Chevrolat (Geonemini) and Apodrosus Marshall (Polydrusini). The analysis produced two most parsimonious cladograms with a length of 167 steps, a consistency index of 36 and a retention index of 73. According to the strict consensus and preferred character state optimisations, the examined species of Lachnopus do not form a monophyletic entity, even though most species are placed in a major L. coffeae–L. guerinii ingroup clade, which stands in sister relationship to Ischionoplus. This major clade is constituted by at least three well-recognisable subgroups, each associated with a particular geographic range in the Caribbean region: (1) a widely distributed L. coffeae–L. lineicollis ‘grade’; (2) the Hispaniolan L. proteus–L. mercator clade; (3) and the L. hispidus–L. guerinii clade with species from Cuba, Florida and Jamaica. This study provides a sound phylogenetic basis for future revisions of Lachnopus and related geonemine genera.

A systematic revision of Mcateella is given including the description of seven new species: M. austera, sp. nov., M. coolgardie, sp. nov., M. esperancensis, sp. nov., M. exocarposa, sp. nov., M. kwoki, sp. nov., M. reidi, sp. nov. and M. schuhi, sp. nov. The following species are redescribed: M. elongata Hacker M. gibber Drake, M. interioris Hacker and M. splendida Drake. Mcateella is defined as a monophyletic group on the basis of clavate guard setae and the stridulatory apparatus. Phylogenetic analysis of the Piesmatidae recognised Eopiesma as the sister-taxon relative to the remaining extant Piesmatidae. The ingroup relationships of Mcateella contained one polytomy. Miespa was found to be the sister taxon to Mcateella, positing a transantarctic relationship. Host plant analysis indicates that Mcateella are not all Acacia specialists as stated in the literature but feed on a wide range of angiosperms.