Trocnada Walker

Dai, Wu & Dietrich, Christopher H., 2012, Review of the Australian leafhopper genus Trocnada with notes on related genera (Hemiptera: Cicadellidae: Iassinae), Zootaxa 3209, pp. 53-66 : 54-55

Trocnada Walker

Trocnada Walker, 1858:103 . Type species: Trocnada dorsigera Walker , by monotypy..

Abelterus Stål, 1865: 157 . Type species: Abelterus incarnatus Stål , synonymised by Distant 1908: 100

Description. General color red, brown or tan, with or without numerous small black dots on dorsum. Body cylindrical, long and narrow. Ventral surface flattened. Vertex, pronotum and frontoclypeus densely transversely striated. Head with transverse bend at level of antennal ledges, crown not delimited, vertex and dorsal half of frontoclypeus nearly vertical, postfrontal suture visible as arch between median ends of antennal ledges; ventral half of frontoclypeus and rest of lower part of face oriented horizontally on slightly concave ventral surface; anteclypeus rectangular or slightly tapered distally, slightly gibbous medially, apex convex; transclypeal suture incomplete; lorum as broad as anteclypeus, extended nearly to lower genal margin, lateral suture incomplete dorsally; gena broad but not strongly produced laterally, lateral margin weakly sinuate, largely concealing proepisternum. Antennal ledges strong, transverse or slightly oblique, antennal pits deep, antennae short. Ocelli large, on vertex about midway between eye and midline, mesad of antennal pits, well separated from frontoclypeus, distinctly closer to antennal ledge than to dorsal margin of head. Pronotum strongly declivous anteriorly, slightly narrower to slightly wider than head in dorsal view, lateral margins carinate. Forewing long and narrow, venation complete, with several accessory costal veinlets adjacent to and distad of outer anteapical cell, appendix well developed, slightly narrower inner apical cell, extended to apex of wing, inner apical cell long and narrow, completely membranous, other apical cells with some semiopaque sclerotization. Front femur with AM1 undifferentiated, intercalary group consisting of irregular double row of moderately stout setae continuous with setae of similar size in basal AV group; tibia with dorsal surface flattened and bicarinate, setae numerous but poorly differentiated. Hind femur macrosetae 2+2 except for 2+2+ 1 in female T. minuta , with penultimate pair subequal in size; tibial rows PD, AD, and AV with 16 – 31, 9 – 12, and 13 – 14 macrosetae, respectively; AD without small setae between macrosetae; tarsomere I with single dorsoapical macroseta; plantar surface bare, pecten with 6 or more platellae.

Male genitalia: Pygofer triangular, gradually tapered posteriorly, distal lobe partially separated from basal section by dorsal and ventral clefts, dorsal margin straight, acutely angulate posterodorsally; ventral process arising as thickened area near base and separated from distal lobe near midlength of margin, apex expanded, bilobed; macrosetae absent, several short setae along posterior margin. Subgenital plates elongate, close together at base, strongly divergent and narrowed distally, with many long hair-like fine setae on ventral side, without macrosetae, basal half concealed by enlarged pregenital sternite. Style well developed, articulated to connective well below aedeagal atrium, apophysis elongate, sigmoid at base, narrowed distally, slightly curved dorsally near apex, with numerous denticuli preapically on ventral surface. Connective Y-shaped, stem longer than arms. Aedeagus simple, tubular basally, narrowed distally, curved dorsally in lateral view, dorsal apodeme developed, with weak to well developed dorsolateral lobes in posterior view; shaft with pair of slender processes distad of gonopore, apex tapered in lateral and posterior views; gonopore apical on posterior surface.

Female genitalia: Abdominal sternite VII slightly longer than sternite VI, partially concealing base of ovipositor in repose, posterior margin shallowly to deeply emarginate. First valvifers fused anterodorsally, valvulae with dorsal sculpturing imbricate. Second valvulae with bases of rami extended dorsad slightly beyond base of valvifers, blades evenly curved and moderately broad throughout length, dorsal margin with two prominent preapical teeth.

Biology. All three recognized species appear to be broadly distributed in forests throughout Australia. They have most commonly been collected at lights. Trocnada dorsigera and T. alpina have been collected from Eucalyptus (Myrtaceae) foliage and T. minuta is recorded from Tea Tree ( Leptospermum sp., Myrtaceae ).

Distribution. Australia.

Comparative Notes. Comparison of specimens of Trocnada from Australia with Trocnadella from Asia revealed that, although species of the two genera are somewhat similar in size, shape, and external appearance, there are fundamental differences in the male genitalia. Trocnada has the pygofer with a flaplike distal lobe partially separated from the base by dorsal and ventral clefts and a ventral process extended beyond the midlength; the subgenital plates are elongate and only partially concealed by the pregenital sternite; and the connective is Yshaped and articulated to the aedeagus ( Figs. 2 – 4 ). In these respects, Trocnada resembles Thalattoscopus Kirkaldy and Batracomorphus Lewis (Iassini) ( Fig. 7 A – F), both well represented in the Australian region. In contrast, Trocnadella has the pygofer lacking both a flaplike distal lobe and a ventral process; the subgenital plates are short and are completely concealed by the pregenital sternite; and the connective is absent or completely fused to the aedeagus ( Fig. 6 A – F). Thus, in the structure of the male genitalia, Trocnadella does not closely resemble that of Trocnada but is instead most similar to a group of Oriental iassine genera that includes Hyalojassus Evans , Coriojassus Evans , and Sinojassus Dai et al. (2010) . Moreover, although Trocnadella has the anterior portion of the pronotum and the vertex of the head more or less vertical, as in Trocnada , Trocnada has a distinct angle at the level of the antennal ledges, with the ventral part of the head flat or concave. In contrast, the profile of the head in Trocnadella , including the ventral portion, is more or less smoothly convex, as in most other Iassini. We therefore retain Evans’ (1947) original definition of Trocnadini, which included only the type genus. A preliminary morphology-based phylogeny placed Trocnada as sister to Thalattoscopus , which is restricted to Australia and New Guinea (Dai & Dietrich 2010). A more comprehensive treatment of the phylogeny of Iassinae is underway and will address the status and relationships of the various tribes previously recognized within the subfamily.

Figures

FIGURE 2. Dorsal and lateral habitus. (A – D) Trocnada alpina; [(A – B) female; (C – D) male]; (E – J) Trocnada minuta [(E – H) female; (I – J) male].

FIGURE 3. Trocnada dorsigera Walker (A) Pygofer, lateral view. (B) Pygofer, ventral view. (C) Subgenital plate, ventral view. (D) Pygofer ventral process, lateral view. (E) Aedeagus, caudal view. (F) Aedeagus, lateral view. (G) Style, lateral view. (H) Connective.

FIGURE 4. Trocnada alpina Evans (A) Pygofer, lateral view. (B) Pygofer, ventral view. (C) Aedeagus, lateral view. (D) Aedeagus, caudal view. (E) Pygofer ventral process, lateral view. (F) Pygofer ventral process, ventrocaudal view. (G) Subgenital plate, ventral view. (H) Style, dorsal view. (I) Style, lateral view. (J) Connective.

FIGURE 6. Trocnadella arisana (Matsumura) (A) Pygofer, lateral view. (B) Pygofer, ventral view. (C) Aedeagus, connective and style, caudal view. (D) Aedeagus, connective and style, lateral view. (E) Pygofer ventral process, caudolateral view. (F) Subgenital plate, lateral view.

FIGURE 7. Batracomorphus trunctus (Li) (A) Pygofer, lateral view. (B) Connective, ventral view. (C) Subgenital plate, ventral view. (D) Pygofer ventral process, caudolateral view. (E) Aedeagus, lateral view. (F) Apex of aedeagus, caudal view. (G) Style, lateral view.