Isoxya, Simon, 1885

Agnarsson, Ingi, Starrett, James, Babbitz, Zachary & Bond, Jason E., 2023, Discovery and Genetic Characterization of Single Cohort Adult Colonies With Male Aggregations, and Preliminary Evidence for Lekking in a Malagasy Kite Spider (Isoxya,, Insect Systematics and Diversity 7 (1), pp. 1-15 : 5

Genus ISoxYa Simon, 1885

Type species. Gasteracantha cicatricosa C. L. Koch, 1844 Diagnosis: Isoxya females differ from species of African and Malagasy Gasteracantha by the lack of a ventral tubercle between the spinnerets and the epigyne and the location of sigilla number 6 ( Fig. 2 ) ‘sigille 6 ayant migré en avant de la base de l’épine 2’ ( Emerit 1974). They are separated from all other Gasteracanthinae by the chitinous edge of the epigyne that is shaped like a ‘braced’ or ‘ogee’ arch ( Figs. 5 and 8 ); ‘epigyne présentant un rebord chitineux ondulé en accolade’ ( Benoit 1962a). Mature Isoxya males can be distinguished from other African and Malagasy gasteracanthines by six prominent abdominal spines ( Figs. 9–11 ), when present, unlike in other genera where the spines are rudimentary, if present at all; the carapace and cephalothorax being ‘more or less quadrangular’ ( Scharff and Coddington 1997) ( Fig. 9 ) as opposed to the ‘pear shaped’ (Ibid.) carapace of Gasteracantha males from this area; and the embolus of the palp being a broad structure, with a thickly sclerotised part and a pars pendula ( Figs. 12, 14–16 ), as opposed to a simple, thin embolic tip found in African and Malagasy Gasteracanthinae . The female-biased sexual size dimorphism in most

Isoxya species, where typically the males average ≤1.0 times smaller than the females (with exceptions of I. penzoides Simon, 1887 and I. tabulate ( Thorell, 1859) , which approach 2.0 times smaller), is not as extreme as the sexual size dimorphism (SSD) seen in the majority of the Gasteracanthinae species found in Madagascar and Africa; Acrosomoides ( Simon, 1887) ≥3.0, Augusta (O. Pickard-Cambridge, 1877) ≥2.5, Gasteracantha ≥2.5 (with males occasionally ≥4.0 times smaller), Hypsacantha ( Dahl, 1914) ≥1.5, Thelacantha (van Hasselt, 1882) ≥3.5, Togacantha ( Dahl, 1914) ≥3.0 – all female-biased (data Williams original or converted from Emerit 1973, 1974; 1982).

Species composition: I. basilewskyi Benoit & Emerit, 1975 ; I. cicatricosa (C. L. Koch, 1844) ; I. cowani ( Butler, 1883) ; I. mahafalensis Emerit, 1974 ; I. milloti Emerit, 1974 ; I. mossamedensis Benoit, 1962a ; I. mucronata ( Walckenaer, 1841) ; I. nigromutica ( Caporiacco, 1939) ; I. penizoides Simon, 1887 ; I. reuteri ( Lenz, 1886) ; I. semiflava Simon, 1887 ; I. somalica ( Caporiacco, 1940) ; I. stuhlmanni ( Bösenberg & Lenz, 1895) ; I. tabulata ( Thorell, 1859) ; I. testudinaria ( Simon, 1901) ; I. yatesi Emerit, 1973 ; I. manangona n. sp.

Distribution: Central, East, South & West Africa, Madagascar, Yemen

Species concept: Species concepts are critical components of taxonomic hypotheses ( Bond et al. 2022). We employ the diagnosable interpretation of the phylogenetic species concept ( de Queiroz 2007).

Figures

Plate 1. Figs. 2–8. Female: dorsal (Fig. 2), ventral (Fig. 3), side (Fig. 4); epigyne: ventral (Fig 5), posterior (Fig. 6), spermatheca dorsal (Fig. 7); line drawing: epigyne ventral (Fig. 8).

Plate 2. Figs. 9–17. Male: dorsal (Fig. 9), ventral (Fig. 10), side (Fig. 11); palp: dorsal (Fig. 12), ventral (Fig. 13), retrolateral (Fig. 14), prolateral (Fig. 15); line drawings:dorsal palp (Fig. 16), median apophysis (Fig. 17).