Phaeoxantha (Euphaeoxantha) bucephala (W. Horn, 1909)

Moravec, Jiří & Dheurle, Charles, 2023, Taxonomic and nomenclatorial revision of the Neotropical genus Phaeoxantha Chaudoir (Coleoptera: Cicindelidae), Zootaxa 5386 (1), pp. 1-83 : 64

Phaeoxantha (Euphaeoxantha) bucephala (W. Horn, 1909)

( Figs 270–282 )

Megacephala (Phaeoxantha) bucephala W. Horn, 1909b: 284–286 , pl. 9, fig. 12.

Phaeoxantha bucephala : Horn 1921: 149–150.

Megacephala (Phaeoxantha) bucephala : Wiesner 1992: 45

Phaeoxantha bucephala : Cassola & Pearson 2001: 11.

Phaeoxantha bucephala : Wiesner 2020: 30.

Type locality. Argentina: Santiago del Estero .

Type material. Lectotype (designated here) ♂ in SDEI labelled: “ Argentinien ” [printed] / “ Santiago del Estero ” [handwritten] // “Steinbach / Moser” [handwritten] // “Dtsch. Entomol. / Institut Berlin” [printed] // “ Megacephala / bucephala W. H. ” [handwritten] // “Type! / coll. W. Horn ” [printed] // “ Syntypus ” [red, printed] // “ Coll. W. Horn / DEI Eberswalde” [printed] // “bucephala / mihi” [large, greenish collection label with black frame] // “ SDEI coleoptera / # 302350” [printed] . Paralectotype. 1 ♀ in SDEI with same label data except for: “ SDEI coleoptera / # 302351” .

Other material examined. 1 ♂ in CCJM (ex JWCW): “ Paraguay Est. Agropil / dep. Boqueron / Rio Pilcomayo / 21.X.1990, U. Drechsel leg.” . 1 ♂, 1 ♀ in COSJ , 2 ♂♂, 2 ♀♀ in CCJM (ex COSJ): “ Bolivia – Santa Cruz depart./ N. Camiri, dry river ground / 18°59´43´´S, 63°31´50´´W / 20.I. 2020, 500 m / O Šafránek et M. Amaya lgt.”

Differential diagnosis. Adults of Phaeoxantha (P.) bucephala are 20–25.3 (LT 25.2) mm long, 8.00–10.3 (LT 10.2) mm wide. The species is immediately recognizable due to its elytra ( Figs 270–271 , 281, 282 ), which are almost uniformly oval-shaped in both sexes yet wider and notably stout in male (widest below middle), but never distinctly dilated posteriad as in males of the following three species. First three protarsomeres in male ( Fig. 278 ) only slightly dilated (unique character within the genus). Male mandibles ( Figs 273–274 ) distinctly aberrant-shaped, usually with only three teeth (and basal molar) with terminal teeth notably short, wide and abruptly pointed (in most examined males the teeth are more or less worn or broken); second tooth in right mandible tightly appressed to the terminal tooth, third tooth notably distant from second, fourth tooth missing (in LT developed but anomalously placed inward the mandible – Fig. 273 ); female mandibles ( Fig. 275 ) normally shaped and with four teeth (fourth tooth tiny), yet distinctly asymmetrical: third tooth in right mandible acute and notably longer than second tooth. Pronotum ( Fig. 279 ) distinctly trapezoid, posterior lobe markedly narrower than anterior lobe and disc; discal surface indistinctly coriaceous wrinkled in middle, appearing glabrous. Aedeagus ( Fig. 280 ) comparatively short, length 5.30 mm, widest in middle, width 1.00– 1.05 mm).

Distribution. Obviously occurring in a large area of the Rio de la Plata Basin, known from Argentina and Paraguay, but also from southern Bolivia, as summarized by Wiesner (2020), who listed it also from south-western Brazil, and from Argentinean provinces of Chaco, Formosa, Jujuy, Salta, Santiago del Estero (type locality) and Tucumán (previously by Wiesner & Bandinelli 2014). Examined specimens from the Bolivian department of Santa Cruz were taken on bed of a dry river; other Bolivian records are from rather smaller river beds in semi-humid Tucuman forest near the town of Camiri (Ondřej Šafránek, pers. com.). Person et al. (1999a) listed a number of records from the Bolivian departments of Santa Cruz and Tarija (Gran Chaco). For the ecology and biology, including developmental stages, see Zerm & Adis (2001a, b, c).

Figures

FIGURES 270–273. Phaeoxantha (Euphaeoxantha) bucephala W. Horn, two syntypes from Santiago del Estero, Argentina (SDEI). 270–271—habitus: 270—♂, 25.3 mm, LT; 271—♀, 23.3 mm, PLT; 272—original labels of the LT; 273—mandibles and labrum, ♂, LT. Bars = 1 mm. Image credit Kevin Weissing.

FIGURES 274–282. Phaeoxantha (Euphaeoxantha) bucephala W. Horn. 274–275—mandibles: 274—♂, “Brazil, Amazonas”; 275—♀, Bolivia, N. Camiri (COSJ); 276–277—labrum: 276—♂, “Paraguay, Rio Pilcomayo” (CCJM ex JWCW) 277—♀, Bo- livia, N. Camiri (COSJ); 278—protarsus, ♂, ibid (CCJM); 279—pronotum, ♂, Bolivia, N. Camiri (COSJ); 280—aedeagus, Rio Pilcomayo (CCJM); 281–282—elytron: 281—♂, Bolivia, N. Camiri (CCJM); 282—♀, ibid (COSJ). Bars= 1 mm.