Genus Fitchiella Van Duzee, 1917

= Naso Fitch, 1856: 396 (original description), homonym of Naso Lacepède, 1801 (replaced by Fitchiella in Van Duzee 1917: 740)

Type species. Naso robertsonii Fitch, 1856 (in original combination, by monotypy)

Amended diagnosis. Small, stout planthoppers (males 1.8–4.0mm, females 3.0– 5.5mm), coloration black to off-white.

Head. Vertex very short (Fig. 1), approximately two times as wide as long at midlength (robertsonii -group, excepting F. fitchii) to four times as wide as long at midlength (melichari -group and F. fitchii). Frons and clypeus greatly projected, resulting in “snout-like” appearance of the head (“snout” length varying between species). Central plate of frons bordered by numerous sensory pits arranged in two rows on either side within lateral plates of frons (Fig. 1); proximal row long, trailing from base (bordering vertex) to apex (bordering clypeus) of frons; second row shorter, usually with no more than four sensory pits, tracing margin of eye; followed by lateral carinae from eye to clypeus. First row of sensory pits of frons occasionally continuing to lateral face of clypeus (no more than two sensory pits on each side). Head nearly glabrous (i.e., F. robertsonii) or moderately (i.e., F. rufipes) to significantly (viz. F. minor) setaceous. Clypeus laterally expanded at apex, creating bulbous appearance of “snout” apex (robertsonii - group) or apically constricted, creating acutely-pointed appearance of “snout” apex (melichari -group). Eyes large, projecting significantly past hind margin of vertex.

Thorax. Pronotum with prominent median carina, bearing numerous sensory pits on disc; paranotal region significantly curved onto lateral surface of thorax (“lateral lobe of pronotum” of Freitas et al. 2020); paranotal region bears 3–4 sensory pits (robertsonii -group) or 4–6 sensory pits (melichari -group). Mesonotum tricarinate; absent of sensory pits within inner margins of lateral carinae, bearing numerous sensory pits on disc exterior to lateral carinae. Forewings usually brachypterous, venation highly reticulate. Tibiae of forelegs expanded to varying degree (Figs. 14A–C).

Abdomen. Abdomen patterned with contrastingly dark and pale markings (robertsonii -group) or entirely black (melichari -group). Abdominal tergites bearing median ridge; bearing numerous sensory pits (approximately 6–10 per tergite on each side of abdomen, following forewings). Abdominal sternites setaceous.

Male terminalia. Gonostyli hook-like; constricted at apex and base, medially expanded, acutely pointed and dorsally curved at apex. Periandrium subtle and sheath-like, almost surrounding aedeagus, bilaterally symmetrical, apically bilobed; apical third expanded and directed ventrally, terminating as an obtusely-rounded lobe, ventral margin sometimes excavated at “joint” of curve (e.g., F. albifrons, F. fitchii, F. mediana); dorsal margin concave, appearing to form subapical dorsal protrusion preceding curve (excepting F. albifrons). Aedeagus bearing two hook-like process apically, variably directed (often one directed ventrocephalad and the other directed dorsocaudally).

Distribution. Southern Canada to Panama.

Remarks. This genus is very similar to Bruchomorpha Newman, but differs in the expansion of the foretibiae, which are often foliate in Fitchiella (Fig. 14). A subtle difference in the male terminalia is observed between the two genera, though its significance remains unclear: the periandria of most Fitchiella species are concave at the dorsal margin (except in F. albifrons) and bear a dorsal protrusion before expanding and curving ventrally at the apical third (see Doering 1941, plate XVI, fig. 1–5). This feature is not typically found in Bruchomorpha, particularly in those species closely related to the type species, B. oculata (see Doering 1940, plate XXII).

The composition of Fitchiella is controversial. The molecular and morphological analyses of Catanach (2013) and Freitas (2019) suggest that Fitchiella is derived within Bruchomorpha as presently composed. The analyses in Freitas (2019) utilized morphological, molecular (H3 + 12S + 16S + 28S), and combined traits. The results suggest two lineages of Fitchiella based on the four species used in the analysis: Fitchiella brachyrhina, F. robertsonii, F. rufipes, and F. zahniseri. A lineage composed of F. brachyrhina, F. robertsonii, and F. zahniseri was often resolved as a clade, while F. rufipes resolved as a separate lineage (Freitas 2019, figs. 6–9). Fitchiella was resolved within Bruchomorpha in all analyses. However, preliminary morphological study suggests that Bruchomorpha itself is too broadly composed. The polymorphic composition of the Bruchomorpha - Fitchiella clade warrants further review; we find it unlikely that Bruchomorpha will stand as a genus as currently comprised upon further analyses.

Morphologically, Fitchiella can be segregated into two species groups (Table 1), consistent with the analyses of Freitas (2019). The robertsonii -group (Figs. 1–9) represents the genus in the strict sense. The projection of the head of these species is apically bulbous/expanded and rounded and, if laterally compressed, only weakly so; the vertex is also two times as wide as long at the midlength (excepting F. fitchii, which is about three and a half times as wide as long). These species are pallid in color with numerous dark markings; the sensory pits of the abdomen are surrounded by dark longitudinal streaks. While the foretibiae of members of this group are expanded (the primary diagnostic trait of Fitchiella in comparison to other Nearctic caliscelid genera), members of the group vary from slight foretibial expansion (i.e., F. robertsonii, F. rugosa comb. nov.) to the expansion appearing foliate (F. fitchii). This contrasts with the melichari -group (Figs. 11–13) which almost always bears distinctly foliate foretibial expansions (excluding F. albifrons). The robertsonii -group, distributed from southern Ontario to Panama, is composed of Fitchiella brachyrhina, F. fitchii (Figs. 8–10), F. robertsonii (Figs. 5–7), F. rugosa comb. nov., and F. zahniseri.

The melichari -group consists of the remaining species in the genus: Fitchiella albifrons (Figs. 11A, 12A, 13A), F. grandis (Fig. 11B, 12B, 13B), F. mediana (Fig. 11C, 12C, 13C), F. melichari (Fig. 11D, 12D, 13D), F. minor (Fig. 11E, 12E, 13E), and F. rufipes (Fig. 11F, 12F, 13F). This group is comparable to Bruchomorpha, composed of dark (often entirely black) species with the projections of the head laterally compressed without any apical expansion. Also similar to Bruchomorpha is the very short vertex, which is about four times as wide as long at the midlength (i.e., Freitas et al. 2020, figs. 6B, 6E). The group is separated from Bruchomorpha by the significant foliate expansion of the foretibiae (Fig. 14, excepting F. minor)]. The melichari -group is mostly restricted to the desert southwest of the United States. The differentiation of most of these species—namely F. grandis, F. mediana, F. melichari, and F. rufipes —is unclear and deserves further consideration. Some species (viz. F. grandis, F. melichari, and F. minor) were described from females, leaving the male forms unknown. A collection of undetermined Fitchiella specimens from Kansas State University could not be identified confidently because of the difficulty of diagnosing species concepts. A comprehensive taxonomic review is needed to assess species limits. Due to the somewhat aberrant morphology of the species Fitchiella albifrons and F. fitchii compared to the other members of their respective groups, we prefer to create informal species groups instead of describing a new genus for the melichari -group.

Species composition of Fitchiella

Fitchiella albifrons Lawson, 1933

Fitchiella brachyrhina Freitas, Dietrich & Takiya, 2020

Fitchiella fitchii (Melichar, 1906)

Fitchiella grandis Lawson, 1933

Fitchiella mediana Lawson, 1933

Fitchiella melichari (Ball, 1910)

Fitchiella minor Lawson, 1933

Fitchiella robertsonii (Fitch, 1856)

Fitchiella rufipes Lawson, 1933

Fitchiella rugosa (Metcalf, 1923) comb. nov.

Fitchiella zahniseri Freitas, Dietrich & Takiya, 2020