Barolineocerus chiasmus Freytag, 2008

Praciano, Daniel Lucas, Dietrich, Christopher H. & Takiya, Daniela Maeda, 2025, Taxonomic revision of the Neotropical leafhopper genus Barolineocerus Freytag, 2008 (Hemiptera: Cicadellidae: Eurymelinae: Chiasmodolini), with descriptions of three new species and an updated key to species, Zootaxa 5653 (4), pp. 451-485 : 466-468

Barolineocerus chiasmus Freytag, 2008

(Figs. 1I–L, 3A–C, 10A–L)

Barolineocerus chiasmus Freytag, 2008: 58 , figures 2, 5, 32–34.

Type locality: 33 km SE Roura on Kaw Rd., Roura, French Guiana.

Diagnosis (based on material from MNHN). Pronotal macula extends to anterior half or almost to hind margin of pronotum (Figs. 1I, 3A). Claval macula extends distinctly beyond scutellum apex (Figs. 1I, 3A). Abdominal sternite II apodeme extending slightly beyond posterior margin of sternite III ( Figs. 10B ). Pygofer posterior margin with short ventral process; with long and slender median process, sinuous, extending to anal tube, sharply pointed at apex ( Figs. 10C–D ). Valve with anterior margin sinuous and posterior distinctly posteriorly projected ( Fig. 10E ). Subgenital plate without dorsal process; apex abruptly pointed ( Figs. 10F–G ). Aedeagus with dorsal median process; with dorsal subapical ridge; with ventral transverse ridge at median fourth of shaft ( Figs. 10K–L ). Anal tube, laterobasal process with base angulate at anterior margin, apex angulate at anterior margin ( Figs. 10C–D ).

Measurements (mm). Males (n= 2), total length (to apex of forewing): 4.16–4.33; median length of crown: 0.34–0.34; length of crown close to eyes: 0.31–0.32; width of head: 1.50–1.54; width of crown between eyes: 0.81–0.82; length of pronotum: 0.44–0.53; length of scutellum: 0.71–0.79; width of pronotum: 1.36–1.37; width of scutellum: 1.03–1.08; length of face: 0.90; width of face between eyes: 0.80; distance between ocelli: 0.36; ocellocular distance: 0.20; length of clypeus: 0.33; basal width of clypeus: 0.19; apical width of clypeus: 0.27; length of forewing: 3.43–3.57.

Holotype condition. Body covered with sparse lepidopteran scales, tibiae of both hind legs lost.

Distribution. French Guiana ( Régina, Roura ).

Type examined. 1♂, holotype of Barolineocerus chiasmus , “ FRENCH GUIANA \ 33 km SE Roura on\ Kaw Rd. 1-XII-2002 \ J. E. Eger coll.”, “N04°34.135'\ W052°11.150'\ 227 m MV light”, “Muséum Paris\ MNHN ( EH)\ 4100”, “ Holotype \ Barolineocerus \ chiasmus \ P. H. Freytag 2006”, MNHN .

Additional material. FRENCH GUIANA: 1♂, “GUYANE FRANÇAISE\ Ellisco [ Ellisco type trap] \ 27.1.1984 \ G.TAVAKILIAN REC.”, “ROUTE DE KAW\ PK 5”, “Museum Paris \ MNHP( EH)\ 1625”, “ B. [ Barolineocerus ] chiasmus \ comp. [compared with] type ”, MNHN ; 1♂, “French Guiana: [ Régina ] Petite Montagne Tortue\ 04°19'14.1N – 052°14'27.5W \ Flooded forest \ Terra Firme\ Light trap \ 08.ix.10\ G. Lamarre leg.”, DZRJ ; 1♂, 1♀, “FRENCH GUIANA: 1 km S\ Amazon Natural Lodge , 30\ km SE Roura on Kaw Rd.,\ 3–4-VI-2005, J.E. Eger \ & M. T. Messenger, coll.”, “N04º32.961'\ W052º12.830'\ 288m MV Light”, UKIC .

Remarks. Freytag (2008) provided illustrations of the dorsal view of the head and thorax, male genital capsule (lateral view), subgenital plate (ventral view), connective, style, and aedeagus (ventral view), and undissected female terminalia (ventral view) of B. chiasmus . However, examination of the holotype indicates that his illustrations of the posterior process of the pygofer and the anal tube are slightly inaccurate. The basal 3/5 of the posterior process of the pygofer is somewhat straight, directed caudal-dorsally, then it bends posteriorly (but not at a 90º angle), and the apex is slightly curved in lateral view, posteriorly directed ( Fig. 10C ). In posterior view, the basal 3/5 is convergent, basal 4/5 almost parallel, and then bends again so the apical third crosses the midline, then the apices are divergent ( Fig. 10D ). The base of the laterobasal process of the anal tube is angulate at the anterior margin, making somewhat of a heel, the apex, posteriorly, it is pointed, but it is also angulate at the anterior margin, making somewhat of a heel ( Figs. 10C–D ).

Barolineocerus chiasmus shares characteristics with B. ornatus , B. chicomendesi sp. nov., B. dercyae sp. nov., and B. digitatus sp. nov., specifically in having a pair of elongate median processes on the posterior margin of the pygofer ( Figs. 10C–D ) and the subgenital plates rounded apically ( Figs. 10F–G ). Notably, B. chiasmus closely resembles B. ornatus and B. digitatus sp. nov. in having the aedeagus with a ventral transverse ridge at the apical fourth of the shaft ( Figs. 10K–L ). However, it differs from these species by its simple straight apex of the posterior pygofer processes ( Figs. 10C–D ) compared to multifurcate in B. ornatus and hook-shaped in B. digitatus sp. nov., and its unusual anal tube with laterobasal process with the base and apex angulate on the anterior margin ( Figs. 10C–D ).

Figures

FIGURE 10. Barolineocerus chiasmus Freytag, 2008, male from French Guiana, Régina, MNHN.A, forewing. B, apodemes of sternite II, dorsal view. C, pygofer and anal tube, lateral view. D, pygofer and anal tube, posterior view. E, valve, ventral view. F, subgenital plate, lateral view. G, subgenital plate, ventral view. H, connective and style, dorsal view. I, connective, lateral view. J, style, lateral view. K, aedeagus, lateral view. L, aedeagus, posterior view. ADS: aedeagal dorsal median spine. Scale bars: A= 1.0 mm, B–L= 0.2 mm.