Riekoleon New, 1985

Machado, Renato Jose Pires & Oswald, John David, 2020, Morphological phylogeny and taxonomic revision of the former antlion subtribe Periclystina (Neuroptera: Myrmeleontidae: Dendroleontinae), Zootaxa 4796 (1), pp. 1-322 : 285-286

Riekoleon New, 1985

Type species. Riekoleon convergens New, 1985 , by original designation. Nomenclatural gender: masculine.

Diagnosis. Wings rather narrow and acute, membrane mostly hyaline, but often with numerous brown marks; protibia> 1.5x length of protarsus; male ectoproct with or without posteroventral lobe; female ectoproct without cavisetae; female posterior gonapophysis long, broad, with numerous apical cavisetae.

Description. Head: Vertex weakly raised. Antennae clubbed and elongate; flagellomeres almost as long as wide at base, apical ones wider than long. Palpimacula opening oval-shaped, located medially. Thorax: Pronotum mostly set with short black setae but a few long setae at margins. Miller’s organ present. Wings: narrow and acute; hyaline but with numerous brown marks. Anterior Banksian line present in both wings, but posterior absent. Forewing with subcostal veinlets simple; prefork area slightly wider than posterior area. Hind wing with one presectoral crossvein. Male pilula axillaris present. Legs: Protibia longer than protarsi. Pretarsal claws slightly shorter than half of T5 length. Sense hair absent or reduced. Male Terminalia: Ectoproct in lateral view with ventral margin straight and longer than dorsal margin; mediuncus absent or very small and acute. Female Terminalia: Ectoproct posterior margin rounded with no cavisetae; lateral gonapophyses smaller than ectoproct; posterior gonapophyses broad and set with numerous cavisetae apically; pregenital plate small, almost imperceptible in some species; 9 th tergite membranous digitiform process present.

Distribution ( Figs. 153 , 162 ). Australia: NSW, QLD, SA, WA. Widespread across mainland Australia; few records from central and northwestern areas. The distributions of most Riekoleon species appear to be substantially more restricted in extent than the majority of Periclystus genus group species. In many cases, closely related species appear to occupy allopatric or parapatric ranges (e.g., R. longitudinalis , R. striatus , and R. edwardsi ; R. rudda and R. distivenus ; R. convergens and R. proctus )

Included species (9 spp.; 2 species groups). convergens group (4 spp.; monophyletic): Riekoleon convergens , R. furcatus , R. proctus , R. squamosus sp. nov.; rudda group (5 spp.; monophyletic): Riekoleon distivenus sp. nov., R. edwardsi , R. longitudinalis sp. nov., R. rudda , R. striatus .

Biology. Unknown.

Etymology. Rieko - (from the surname of Edgar Frederick RIEK, Australian entomologist) + - leon (from Greek leon, lion; a traditional antlion genus-group name ending), in recognition of Riek’s contributions to the field of neuropterology.

Comments. New (1985b) created Riekoleon for two species that possess a tubularly produced posteroventral lobe on the male ectoproct. Based on our morphological phylogeny ( Fig. 4 ), we reinterpret the genus in a broader context here. While the shape of the posteroventral region of the male ectoproct continues to be important in diagnosing species within the genus, the conformation of the female posterior gonapophysis, which are long and broad with numerous apical cavisetae, is diagnostic for the genus. Our expanded circumscription of Riekoleon can be divided into two clades, the monophyletic convergens and rudda species groups.

The convergens group contains four species: two originally included in Riekoleon ( R. convergens and R. furcatus ), one transferred from Austrogymnocnemia ( R. proctus ), and one new species ( R. squamosus sp. nov.). The members of this group are close to the original concept of the genus; they are relatively delicate in build with elongate legs and pronotum, wings with numerous brown marks, and a distinctly tubular posteroventral lobe on the male ectoproct. These species are restricted to the eastern parts of Australia (with the possible exception of one examined ANIC specimen from southwestern Western Australia, whose placement remains uncertain because of very poor condition).

The rudda group contains five species: two previously placed in Austrogymnocnemia ( R. striatus and R. edwardsi ), one transferred from Glenoleon ( R. rudda ), and two new species ( R. distivenus sp. nov. and R. longitudinalis sp. nov.). The species in this group have relatively short legs and the posteroventral margin of the male ectoproct is only angled, not tubularly produced. The five species are less uniform in general habitus than those of the convergens group and are collectively distributed over a wider range, including both western and eastern Australia.

The molecular phylogeny of Machado et al. (2019), which included only two of the nine here-recognized Riekoleon species ( R. distivenus sp. nov. [as Austrogymnocnemia sp1] and R. squamosus sp. nov. [as Riekoleon sp.]), placed the species as a paraphyletic group near the base of the Periclystus genus group. Because of the low taxon sampling diversity of the 2019 tree for Riekoleon species, and the extremely short branch lengths in the region of the tree where the Riekoleon species were recovered, we here rely on our morphological tree ( Fig. 4 ) to circumscribe and divide the genus. The morphological analysis recovers the nine-species Riekoleon concept as monophyletic, but with several unresolved polytomies internally.

Figures

FIGURE 4. Strict consensus tree of morphology-based parsimony analysis of species belonging to the former subtribe Periclystina (ingroup, names in black), and outgroups (names in red). Former Glenoleon species are shown on blue branches, former Austrogymnocnemia species on green branches. Numbers above branches are Bremer support values; numbers below branches are bootstrap values (shown where>50%).

FIGURE 153. Distribution of Riekoleon species (part).

FIGURE 162. Distribution of Riekoleon species (part).