Proanaxipha madgesuttonae Heads & Penney

Heads, Sam W., Penney, David & Green, David I., 2012, A new fossil cricket of the genus Proanaxipha in Miocene amber from the Dominican Republic (Orthoptera, Gryllidae, Pentacentrinae), ZooKeys 229, pp. 111-118 : 112-113

Proanaxipha madgesuttonae Heads & Penney sp. n. Figs 1-8

Diagnosis.

Distinguished from congeners by the following characters: (1) head capsule with distinctive posteriorly bilobed colour spot on vertex; (2) presence of crossveins in the proximal part of the mediocubital area; (3) apical field of tegmen entirely dark; and (4) median process of epiphallus short.

Description.

Male: Total body length measured from fastigium verticis to abdominal apex 5.97 mm (Figs 1-2). Head capsule (length 1.26 mm) compressed dorsoventrally; vertex with distinct posteriorly bilobed colour spot (Fig. 4); fastigium verticis broadly rounded; median ocellus situated dorsally, between antennal torulae; compound eyes large, interocular distance 0.64 mm; antennae filiform, scape approximately four times larger than pedicel; maxillary palpi long with apical palpomere triangular and distally concave (see Fig. 2).Pronotum (length 1.02 mm) wider than long, with lateral and marginal areas covered with long setae; disc largely dark with a pale median line not reaching anterior margin; posterior margin sinuous and slightly wider than anterior margin; marginal areas well-demarcated with prominent carinae (Fig. 4). Thoracic sternites polygonal, plate-like and densely pilose, increasing in size posteriorly (Fig. 2). Terminalia obscured dorsally by hind wings (see Fig. 1); subgenital plate pale, broadly rounded with an indistinct median ridge flanked by shallow depressions and the posterior margin shallowly emarginate (Fig. 8); cerci densely setose; epiphallus triangular with pointed apex directed dorsally; ectoparameres lobate.

Tegmen 3.78 mm long with distinct coloration and stridulatory apparatus only partially reduced (Fig. 3); harp elongate, without multiple harp veins; mirror small, lacking dividing vein; lateral field dark with veins running parallel to the costal margin; dorsal field with six crossveins in the basalmost part of the mediocubital area with dark patches running along the stridulatory and harp veins and merging with a large dark spot encompassing most of the proximal cells in the cubital system; apical field entirely dark (Fig. 3). Hind wing long and tightly folded, extending well beyond abdominal apex, with dark remigium and hyaline anal lobe. Prothoracic leg short and robust with a single dark band on the distal half of the profemur and ovoid tympana on both sides of the protibia (Fig. 7). Mesothoracic leg longer than prothoracic leg; mesofemur with single dark band and a prominent ventral sulcus distally; mesotibiae with two dark bands. Metafemur (length 3.54 mm) with a dense covering of setae and bearing two dark spots; one situated just distad of femoral midlength and the second situated apically, encompassing the genicula (Fig. 5). Metatibia (length 2.61 mm) approximately 25% shorter than metafemur and quadrate in cross section, with two small dark spots situated basally; dorsal longitudinal carinae armed with rows of small denticles interspersed distally with stout subapical spurs (3 inner and 3 outer); metatibial apex bearing 2 inner and 3 outer apical spurs (Figs 5-6); median outer apical spur twice as long as the other outer spurs. Metabasitarsus elongate with rows of sharp denticles along the dorsal longitudinal carinae and two apical spurs (1 inner and 1 outer); second metatarsomere much reduced; third metatarsomere long, slender and slightly curved (Fig. 5).

Holotype.

♂: Dominican Republic: Early Miocene (Burdigalian) amber (NHM II 3048).

Etymology. Named in honour of Madge Sutton at the request of Dr Susan Shawcross.

Remarks.

Proanaxipha madgesuttonae is clearly congeneric with the type species Proanaxipha latoca , sharing the partially reduced stridulatory apparatus, a long and straight metabasitarsus, similar metatibial armature and the presence of auditory tympana on bot h faces of the protibia (see Gorochov 2010). Nevertheless, Proanaxipha madgesuttonae differs markedly from Proanaxipha latoca in its colouration. The new species is altogether darker than Proanaxipha latoca , bearing a distinctive posteriorly bilobed colour spot on the vertex of the head capsule (Fig. 4) and a much darker tegmen. The apical field of the tegmen in Proanaxipha latoca is either pale or bears a few diffuse dark patches (see Gorochov 2010, p. 443, fig. 6). In contrast, the apical field in Proanaxipha madgesuttonae is entirely dark (Fig. 3). The holotype of Proanaxipha latoca bears two dark spots on the vertex between the eyes but the rest of the head capsule is pale (see Vickery and Poinar 1994, p. 21, fig. 9). Gorochov (2010) briefly described a number of additional specimens that he tentatively assigned to Proanaxipha latoca . However, all of these differ from the holotype in coloration and Gorochov (op. cit.,p. 444) remarked that they likely represent a complex of distinct species. While the original colouration of the specimen cannot be known with certainty, arthropod colour patterns are often extremely well preserved in amber ( Poinar 1993; Grimaldi and Engel 2005; Penney 2010 and contributions therein). Given the remarkable preservation of the specimen as well as the obvious symmetry of the patterns, it is highly unlikely that they have been altered taphonomically. Morphologically, Proanaxipha madgesuttonae is very similar to the holotype of Proanaxipha latoca and to the specimens recently described by Gorochov (2010). However, the tegminal venation of Proanaxipha madgesuttonae differs in the presence of six crossveins in the basal half of the mediocubital area (Fig. 3). The tegmina are not clearly illustrated in the original description of Proanaxipha latoca making it impossible to determine whether or not these crossveins are present. However, the illustrations of Proanaxipha?latoca presented by Gorochov (2010) show no mediocubital crossveins. The distal parts of the phallic complex visible in the holotype of Proanaxipha madgesuttonae (Fig. 8) are very similar to those illustrated by Gorochov (2010) though the median process of the epiphallus is shorter in Proanaxipha madgesuttonae .