Xestocephalites balticus, Dietrich & Gonçalves, 2014

Dietrich, Christopher H. & Gonçalves, Ana Clara, 2014, New Baltic amber leafhoppers representing the oldest Aphrodinae and Megophthalminae (Hemiptera, Cicadellidae), European Journal of Taxonomy 74, pp. 1-13 : 6-8

Xestocephalites balticus sp. nov.

urn:lsid:zoobank.org:act:FC8D9A1F-FF96-4DD0-8A1D-5C587489CC76

Figs 1C-D , 2G-I

Diagnosis

This species resembles the modern genus Xestocephalus Van Duzee, 1892 in the structure of the head and in the leg chaetotaxy but differs in having the head wider than the pronotum, the crown more

strongly depressed, the forewing elongate, and the front femur lacking an enlarged ventral seta near the midlength.

Etymology

The species name refers to the Baltic region, where the holotype originated.

Material examined

Holotype male, Eocene Baltic amber, Palanga, Lithuania ( INHS).

Description

MEASUREMENTS. (in mm). Body length including forewing at rest 5.3; head width 1.5; pronotum width 1.4; front femur length 0.8, tibia 0.9; middle femur length 0.8, tibia 1.1; hind femur length 1.5, tibia 2.1, tarsus 0.7; forewing length 4.2.

STRUCTURE. Body elongate, weakly depressed, dark brown colored, without conspicuous pattern. Head slightly wider than pronotum; crown well developed, roundly produced, longer medially than next to eye, uniformly shagreen; ocelli well developed but small, on crown just posterad of anterior margin, slightly closer to midline than to eye; transition from crown to face rounded; antennal ledges oblique, weakly developed; antennal pits deep; antenna shorter than half width of head; frontoclypeus weakly convex; lateral margins evenly tapered ventrad from antennal pits to just dorsad of clypeal suture, thence abruptly narrowed; clypeal suture weakly delimited; lateral frontal sutures extended dorsomesad from antennal pits to near dorsal margin of face; anteclypeus parallel-sided, weakly convex, apex rounded, extended slightly beyond genal margin; lorum flat, narrowly separated from genal margin ventrally, bordering anteclypeus for half length; gena broadly rounded; rostrum extended to just beyond base of hind legs. Pronotum depressed smooth, with sparse fine punctures and very inconspicuous transverse striations lateral margin less than half-length of eye, carinate. Exposed part of mesonotum and scutellum together slightly shorter than broad. Front femur chaetotaxy poorly visible in holotype, without conspicuous large ventral setae, tibia without conspicuous dorsal preapical macrosetae, ventral rows with several conspicuous macrosetae. Hind femur macrosetae 2+1+1; hind tibia flattened and bowed, with setal rows PD, AD, AV with 12, 11, and 17 setae, respectively (PV not visible on specimen); with macrosetae of dorsal rows approximately equal in length, AD and PD with approximately equal numbers of macrosetae extended from near base to apex, without short intercalary setae between successive large macrosetae, AV with 3 stout preapical macrosetae in addition to numerous close set, slender setae of approximately equal length; tarsomere I elongate, with conspicuous dorsoapical pair of macrosetae and well differentiated ventral longitudinal row of short, stout setae. Forewings macropterous, venation not visible in holotype; clavus occupying ¾ length of wing, appendix absent. Male subgenital plates short and broad, somewhat compressed, fused along midline, with numerous conspicuous long, fine setae along dorsal and apical margins and few stout setae ventromedially, apices obliquely truncate.

FEMALE. Unknown.

Age and occurrence

Baltic region. Baltic amber, Middle Eocene, ca. 44 Ma.

Remarks

This genus is referable to Aphrodinae based on the position of the ocelli on the crown slightly posterad of the anterior margin and distant from the eye. Among modern aphrodines, it most closely resembles Xestocephalus (Xestocephalini) in the structure of the head. Xestocephalus differs in having the head less strongly depressed and narrower than the pronotum with the gena broader and the anteclypeus strongly flattened. Xestocephalites gen. nov. also differs from most modern aphrodines in having the wings fully macropterous. Species of the related tribe Portanini also have fully developed wings, but differ in having the head narrower, the ocelli on the margin of the crown, and the lorum greatly enlarged.

Specimen notes

The type specimen is embedded in a clear orange-yellow piece of amber but it is partly degraded with the left front leg (femur and segments distad) detached, and parts of the dorsum, including the forewings, largely concealed by air bubbles such that the wing venation is not visible. The anterior margin of the head is obscured by a horizontal fracture plane.

Figures

Fig. 1. Habitus in dorsal and ventral view. A-B. Eomegopthalmus lithuaniensis sp. nov. ♀. C-D. Xestocephalites balticus sp. nov. ♂. E-F. Brevaphrodella nigra sp. nov. ♂. Scale bars = 1 mm.

Fig. 2. A-F. Eomegopthalmus lithuaniensis sp. nov. ♀. A. Crown, pronotum, and mesonotum, dorsal view. B. Face, anteroventral view. C. Right forewing, lateral view. D. Prothoracic leg, lateral view. E. Metathoracic leg, dorsal view. F. Second valvulae of ovipositor, general lateral view. G-I. Xestocephalites balticus sp. nov. ♂. G. Face. H. Apical portion of femur, tibia, and first tarsomere of metathoracic leg, lateral view. I. Subgenital plates, ventral view. Scale bars: A-H = 1 mm; I = 0.5 mm.