Gelae

Abstract: Two new genera of Agathidiini are described and revised: Gelae Miller and Wheeler, new genus and Decuria Miller and Wheeler, new genus. Gelae differs from other agathidiines by having 11 antennomeres, a distinctly 3-segmented antennal club, no supraocular carina, no postocular temporum, 5–4–4 female tarsal formula and obsolete dorsal punctation, or, if present, inconspicuous and not serially arranged. Decuria differs from other agathidiines by having 10 antennomeres. The dramatically poor taxonomic condition of genera in the Agathidiini is discussed and problems are identified. A key to the genera of Agathidiini is presented. The following new combinations are proposed: Gelae parile (Fall), new combination, G. parvulum (LeConte), new combination, and G. cognatum (Matthews), new combination. Each are transferred from Agathidium Panzer. The following new species are described: Gelae rol, new species, G. fish, new species, G. donut, new species, G. baen, new species, G. belae, new species, and Decuria newtoni, new species. A lectotype is designated for Agathidium parile Fall. Notwithstanding certain recent advances in the classification of genera of the leiodid tribe Agathidiini (Angelini and Peck 2000; Newton 1998), monophyly of some of these genera and proposed relationships among them remain in serious doubt. A particular problem is represented by the genus Agathidium Panzer, which is a huge group of several hundred species without a single known unambiguous synapomorphy. The current definition of the genus is based on a character combination with conspicuous exceptions. The genus is defined, in part, as having a distinct 3-segmented antennal club, the clypeus not protuberant, and punctured elytral striae absent. However, some (e.g., Ag. rusticum Fall) have a relatively prominent 5-segmented club, several (e.g., Ag. athabascanum Fall, Ag. laetum Fall, the Ag. sexstriatum-group) have rather prominently anteriorly-protruding anterior clypeal margins and others (e.g., the Ag. sexstriatum-group and several members of the Ag. pulchrum-group) have longitudinally serial punctures on the elytra (Miller and Wheeler in press; Wheeler and Miller in press). The problem is not necessarily the misplacement of species in this genus since many of these species strongly resemble other, more ‘‘typical’’ Agathidium in other less general characters. Other genera have different problems. The genus Anisotoma Panzer appears to be united by apparently plesiomorphic features including a typical leiodid 5-segmented antennal club, protuberant anterior clypeal margin, longitudinally striate elytra (absent in some Anisotoma), and lack of a postocular temporum and carina. Other genera, including Sphaeroliodes Portevin, Stetholiodes Fall, and Pseudoagathidium Angelini are apparently ambiguously defined or are based on characters that vary within the genus Agathidium such that even writing an adequate key is quite difficult. In a recent paper describing a new agathidiine genus, Angelini and Peck (2000) presented a number of characters used to distinguish genera of the tribe, a key to the genera, and a proposal of the phylogeny. However, there are a number of problems with their analysis. For example, the topology they present is not the most parsimonious. When their character matrix is analyzed using all additive character states (as they did) using NONA and the commands ‘‘hold/20,’’ ‘‘mult*20,’’ for tree

Abstract: A cladistic analysis of the tribe Agathidiini Westwood is presented. Agathidiines are slime mould specialists and they are hypothesized to be a monophyletic group consisting of 12 genera (Afroagathidium Angelini & Peck, Agathidium Panzer, Anisotoma Panzer, Besuchetionella Angelini & Peck, Cyrtoplastus Reitter, Decuria Miller & Wheeler, Gelae Miller & Wheeler, Liodopria Reitter, Pseudoagathidium Angelini, Sphaeroliodes Portevin, and Stetholiodes Fall), based on three synapomorphies: epipleuron present to apical third, mesoventrite without longitudinal carina and longitudinal setal lines present on the tibiae. The dataset for phylogenetic analysis comprised 72 characters representing 198 character states derived from adult morphology. These data were analysed using equal weighting and implied weighting (k = 1–6) and supported the monophyly of the tribe based on three unique characters (epipleuron present to apical third, mesoventrite without longitudinal carina, longitudinal setal lines present on tibia) and two homoplastic characters [antennomeres 7–10 (or 6–9) asymmetrical, apical shape of terminal antennomere abruptly tapered]. The topology of IW trees with k = 4–6 was identical with one of three EW trees. Decuria was sister group to the remaining agathidiine genera whereas the following groups were resolved as monophyletic: Anisotoma, Gelae + Liodopria, and Pseudoagathidium (Afroagathidium + Besuchetionella). The clade [Sphaeroliodes rufescens (Agathidium bockshini, Agathidium subcostatum)] was supported in all analyses except for the IW (k = 1) cladogram. The monophyly of Agathidium was not supported at all and was rendered paraphyletic by the placements of Sphaeroliodes, Stetholiodes and the Pseudoagathidium (Afroagathidium + Besuchetionella) clade. Sphaeroliodes is synonymized with Agathidium (syn.n.) resulting in two new combinations [A. acuminatus (Svec) and A. rufescens (Portevin)]. Contractability is a complex character composed of several morphological features that have evolved independently within the agathidiine tree. Conglobation (the ability to roll the body into a ball) has arisen at least twice in Agathidiini.