Acrolithus Freytag & Ma

Zahniser, James N., 2021, Revision of the New World leafhopper tribe Faltalini (Hemiptera: Cicadellidae: Deltocephalinae) and the evolution of brachyptery, Zootaxa 4954 (1), pp. 1-160 : 22-23

Acrolithus Freytag & Ma

Type species: Acrolithus brevis Freytag & Ma, 1988 ; designated.

Acrolithus Freytag & Ma, 1988: 153 [original description, morphology, illustration, new species]; Hamilton, 2000: 452 [morphology, classification]; Zahniser & Webb, 2004: 668, 669 [morphology, classification]; Zanol, 2006: 97 [catalogue]; Zahniser & Dietrich, 2010: 507, 508 [morphology, classification]; Zahniser & Dietrich, 2013: 83, 85 [morphology, classification]; Dietrich, 2017: 398 [classification]; Zahniser, 2007 [online catalogue]; Freytag & Gaiani, 2017 [online catalogue]

Diagnosis. Acrolithus can be distinguished from other genera in the tribe by the subbrachypterous females, submacropterous males, shagreen texture of the crown, frontoclypeus inflated subapically, and the aedeagus with a pair of twice-branched apical processes and without a pair of basal processes.

Body. Male, 3.9–4.6 mm. Female, 5.7–6.5 mm. Body length 3.1x width of pronotum (males), 4.3x (females). Anterior margin of head shagreen next to eyes, sharply angulate to carinate or foliaceous anteriorly. Crown length 1.0x (male)–1.2x (female) interocular width; texture completely shagreen except posteriorly with pair of glossy calluses; depressed near anterior margin. Ocelli small; on anterior margin or slightly dorsad; 1/4–1/3 distance from eye to apex of crown. Frontoclypeus texture shagreen; inflated subapically, in lateral view concave to foliaceous anterior margin of head. Antennal sockets situated near upper corners of eyes. Pronotum carinate laterally; lateral margin about as long as width of eye; rectangular, relatively long; texture shagreen both anteriorly and posteriorly, and posteriorly also with transverse furrows. Scutellum shagreen. Protrochanter with several thin setae. Profemur row AV with 5–6 relatively long, thin setae; intercalary row with 4–6 fine setae; AM1 present; dorsally with pair of stout apical setae. Protibia dorsal setae 1+1 (both at apex of tibia). Mesotrochanter with fine PV seta. Mesofemur row AV with relatively long thin setae. Mesotibia dorsal setae 5+4. Metafemur apical setae 2+2. Metatibia slightly bowed in dorsal view. Metatarsomere I about as long as II and III combined; slightly widening apically; apex with row of 5 platellae, flanked only anteriorly by tapered seta; plantar surface with two rows of stout setae. Male submacropterous; forewing with two anteapical cells, venation irregular—sometimes incomplete or with 1 or more extra crossveins, appendix small, texture shagreen; hindwing with r4+5-m crossvein near apex; with M unbranched; without m-cua crossvein; A1 unbranched. Female subbrachypterous; hindwing reaching or surpassing anterior margin of abdominal tergite III; anterior margin and posterior margin differentiated to wing base.

Color. Male yellowish dorsally; venter dark brown, covering most of face nearly to apex; femora dark brown basally, yellowish apically; tibiae yellowish or brown. Female almost entirely yellowish; darker specimens with some brown coloration as in male, less pronounced.

Male. Pygofer incised dorsally to midlength; in lateral view subrectangular; each side with 15–20 macrosetae posteriorly and dorsally; without anteroventral notch; without teeth or processes. Subgenital plate long, triangular; concave laterally; with 6–7 macrosetae, uniseriate laterally; apices separated. Valve triangular; length about 0.5x width; much longer medially than truncate lateral margin. Connective short, Y-shaped; stem broad. Style broad at base; apophysis short, digitate, slightly curved. Aedeagus with dorsal rim of base of aedeagus pronounced; shaft broad; with pair of long twice-branched processes at apex; gonopore about midway on ventral side; articulated with connective. Phragma not strongly sclerotized. Segment X sclerotized dorsally and laterally.

Female. Pygofer with ~15 macrosetae scattered ventrally and apically. Ovipositor extending slightly beyond pygofer apex. Sternite VII subrectangular; length slighter shorter than width; posterior margin nearly straight. First valvula relatively straight in lateral view; dorsal sculpturing pattern granulose to imbricate, submarginal with distinct unsculptured band on dorsal margin; VSA present, distinctly delimited, texture granulose. Second valvula widened at middle, dorsal margin somewhat humpbacked; ventral margin straight; without dorsal teeth. Gonoplac with numerous short setae ventrally.

Distribution: Venezuela

Remarks. This genus is known only from the type species collected in the state of Trujillo, Venezuela. The female pygofer and ovipositor are illustrated here for the first time. The characters of the ovipositor agree with those that are diagnostic for Faltalini , and thus support its placement in the tribe. The genus was resolved as sister to the Faltala group genera ( Fig. 91 ). It shares several characters with Hecullus including a flattened head, subbrachypterous females, long lateral margin of the pronotum, and densely shagreen texture of the crown and pronotum. The transition from a macropterous male in Hecullus to submacropterous in Acrolithus (an ordered character) supported its sister-group relationship to the Faltala group.

Included species:

Figures

FIGUIRE 91. Strict consensus tree from MP analysis of 51 morphological characters. Numbers below branches are MP bootstrap scores. The plesiomorphic condition is macroptery for both males and females (Hecalocorica bidentata ♂ shown in up- per left). Key stepwise transitions leading to brachyptery occur on clades A (char. 20; forewing of Hecullus bracteatus ♀ and hindwing of Acrolithus brevis ♀ shown), B (char. 22; Acrolithus brevis ♂ shown), and C (chars. 20 & 22; Dietrichana pampas ♀ shown).