Fescennia Stål, 1866

Stroiński, Adam, Łukasik, Piotr, Bartlett, Charles R., Pilet, Fabian, Hasinjaka, Rasolondalao Harin’Hala, Randretsiferana, Safidinirina Armande, Razafindrakotomamonjy, Andrianatenaina & Bahder, Brian W., 2025, New planthoppers in the genus Fescennia (Hemiptera: Derbidae) from screw palms (Pandanus spp.) in eastern Madagascar, with redescription of F. bivittata and an updated key to the genus, Zootaxa 5729 (1), pp. 75-104 : 79-87

Genus Fescennia Stål, 1866

Type species: Phenice bivittata Coquerel, 1859 ( Figs 2–16 )

Amended Diagnosis. Moderate to large planthoppers. Head weakly projected, vertex trapazoidal with anterior transverse carina, lateral margins bearing pits; face with frons quadrate, bearing pits relatively broad, lateral margins approximately parallel-sided, median carina absent.Antennae short. Genae bearing large subantennal foliate process. Wings held upright (perpendicular) to body in vivo ( Fig. 2 ). Costal margin of tegmen with sensory pits basally. Forewing C1 cell elongated, with longitudinal fold (giving appearance of an unattached, spurious vein). Lateral margin of pronotum with carinae (between tegula and head) Hind wing with stridulatory plate at apex of jugal lobe. Pygofer with bilaterally asymmetrical articulated medioventral process, angled dorsad from base. Endosoma bearing 5 processes with varying serration on margins.

Amended Description. Body color usually pale, variably marked; wings transparent with extensive dark markings. Length (including wings) ~ 6-9 mm.

Head. Head from dorsal view narrower or equal to prothorax width. From lateral view, head usually conoid, weakly projected anterodorsal (vertex posteriorly declinate or nearly level).

Vertex trapezoidal in dorsal view (approximately 1.3-3.5x longer at midlength than wide at posterior margin, narrowing anteriorly); with margins carinate, anterior margin of vertex (in dorsal view) bearing transverse carina (anterior margin concave between lateral carinae); posterior margin elevated, shallowly concave in dorsal view; lateral margins keeled, bearing two rows of sensory pits (a prominent row of large pits and an irregular second row of small pits) along lateral margins, disc of vertex sunken (relative to lateral margins); median carina usually present, often obscure. Frons quadrate (or nearly so), distinctly longer than wide, lateral margins subparallel (narrowed in F. analarara sp. nov.), disc of frons with row of large sensorial pits along lateral margins, starting just ventrad of vertex, ending before frontoclypeal suture, smaller pits interspersed among larger pits; disc of frons concave, median carina absent. Compound eye (in lateral view) ovoid, deeply emarginated at antenna; dorsal margin with or without horn-like callus; lateral ocelli present, inconspicuous, median ocellus absent. Gena bearing foliate process extending from beneath antenna, curved dorsocaudad, often in shape of a wide bowl. Antennae short, scape very short and inconspicuous, pedicel globular, bearing many sensory plaques, with or without with subapical cuticular eminence and with or without peg-like sensory structure in form of double setae of varying length, located on a cuticular prominence (pedestal); plate organs with basiconic-like projections of two arrangements: lateral ones arranged horizontally, usually fork-shape and vertical in central part of plate organ; plate organs surrounded by a ring of elevated spines partially directed inwards.

Frontoclypeal suture almost straight. Clypeus elongated, at frontoclypeal suture as wide as frons; postclypeus with lateral and median carina; anteclypeus with only median carina. Rostrum exceeding hind coxae, apical segment as long as wide.

Thorax. Pronotum relatively short (subequal to vertex in midlength), in lateral view anteriorly declinate, mostly raised above level of vertex; from dorsal view anterior margin following contours of head, posterior margin concave; tricarinate with median carina distinct, lateral carinae tracing anterior margin; postocular carina present; paradiscal region proximately quadrate, usually reaching level of ventral margin of antenna, ventral apex rounded.

Mesonotum in lateral view convex, raised above level of pronotum, ascending from base and ending at the base of scutellum; disc of scutellum flattened; in dorsal view slightly longer in midline (including scutellum) than wide in lateral angles; lateral angles of the mesonotum placed caudad of midlength (including scutellum); disc of mesonotum tricarinate, median carina reaching scutellum; lateral carinae not connected with median, converging posteriorly, shorter and partly curved not touching posterior margin and not surpassing of the level of lateral angles of mesonotum; scutellum wide with lateral ridges, not continue to the tip of scutellum; tip of scutellum blunt. Hind tibiae slender, longer than femur, without lateral spines; metatibiotarsal formula 5: 5–6: 5–6.

Forewings held upright (perpendicular) to body in vivo ( Fig. 2 ). Forewing distinctly elongated, narrowly spatulate widest near 2/3 length, costal and claval margin subparallel, costal margin with sensory pits basally; claval margin about fusion of valval veins concave; posterior margin concave in apical region of MP 1+2 field; costal margin with sensory pits at basal part. Basal cell very narrow and elongated; ScP+R+MP arising from leaving basal cell as short common stem and forking distinctly before fusion of claval vein Pcu and A 1. Forking sequence of longitudinal veins ScP+R→CuA→MP; all first forks placed before tip of clavus. Branching pattern RA 2-branched, RP 3-branched, MP 5 or 6 -branched (MP 3+4 always single), CuA 1 2-branched; branches of CuA 2 anastomosed to form closed C5 (procubital) cell with vein CuA 1. Longitidunal vein MP 3+4 fused at short distance with CuA1a or connected by transverse veinlet. Forewing C1 cell extremely elongated, with longitudinal fold (giving appearance of an unattached, spurious vein); C3 cell long without sclerification, C5 shortest also without sclerification. Cell length sequence C1→C3→C5. Transverse veinlet icu present and additional false vein sclerification between CuP and icu present.

Clavus closed; ending before midlength of tegmen; composite vein Pcu+A1 reaching wing margin distinctly before CuP; claval veins Pcu and A 1 joined together before middle of clavus, clavus always without any transverse veinlets but false veins (sclerification) present in some species. Hind wing distinctly narrow and shorter than forewing. Longitudinal vein ScRA with single terminal, RP with single terminal, CuA with 3 branches: CuA 1 2- branched, CuA 2 single; CuP single; A 1 and A 2 single reaching posterior margin; 2 transverse veinlets r-m (curved) and m-cu (straight) present. Jugal lobe distinctly separated from rest of hind wing with distinct stridulitrum, situated at apex of jugal lobe. Two pairs of large glands on dorsolateral surface of tergits 7 and 8 of both sexes present ( Figs 10A–D ).

Male terminalia. Pygofer in lateral view narrow, irregular in shape, inclined anteriorly, caudal margin concave (often with dorsolateral angle projected), anterior margin sinuate; in ventral view, medioventral process articulated, elongate and asymmetrical.Gonostyli slightly asymmetrical.in lateral view spatulate, dorsal margin bearing a variably developed proximal dorsal lobe and a hooked process near midlength; in ventral view, gonostyli often medially arched, bearing a variably developed medial process proximally. Aedeagus with shaft weakly upcurved, simple bearing complex endosoma bearing multiple elongated (often flattened, serrated and mostly retrorse) processes. Anal tube from lateral view slender (especially distad of paraproct) and elongated, apex often downcurved; from dorsal view broad (apex sometimes bilobed). Paraproct small, often inconspicuous from lateral view.

Remarks. Fescennia is recognizable from other Phenicini by the articulated medioventral process. Other genera, such as Paraphenice Muir , Phenice Westwood and Metaphenice Emeljanov possess strongly asymmetrical processes, but they are contiguous with the pygofer (not articulated). Based on wing shape and aedeagal structure, Paraphenice is the most similar genus (from within the Phenicini ). Paraphenice are usually pale taxa with wings held tectiform in repose, the vertex is longer than wide and the medioventral process is fixed and symmetrical ( Locker et al. 2009, Bahder et al. 2024b). The frons of Paraphenice tends to be narrower than Fescennia (e.g., Locker et al. 2009, figs. 6C, 7C; Bahder et al. 2024b, fig. 4C).

Interestingly, a genus currently in the tribe Cenchreini (Bourgoin 2025) , Aethocauda Williams , is similar to Fescennia as it also possesses an asymmetrical, articulated medioventral process and has a similar structure to the aedeagus with serrated “fins” and a similar wing structure. In Williams (1976), it is stated that “It runs to couplet 15 ( Paraphenice Muir , Fescennia Stål ) in Fennah’s (1952) key of Cenchreini ”. It appears Aethocauda is incorrectly placed in the Derbinae and belongs in Phenicini of the Otiocerinae . Given the morphological similarities, Aethocauda may be a synonym of Fescennia . Aethocauda is here transferred to the Phenicini . It appears this genus was missed in Emeljanov (1995).

Holzinger et al. (2008) reported two species attributed to Fescennia from the Seychelles that were subsequently ( Locker et al. 2009) moved to Paraphenice ,in the original designation by Muir (1925).

Figures

FIGURE 2. Adult Fescennia bivitatta aggregating on Pandanus sp. (Photo courtesy: Daniel Austin – iNaturalist danielaustin; observation 175711491).

FIGURE 3. Adult male habitus of Fescennia bivitatta in ethanol; (A) lateral view and (B) dorsal view.

FIGURE 4. Adult male of Fescennia bivitatta in ethanol; (A) head, pronotum and mesonotum dorsal view, (B) head, pronotum and mesonotum lateral view and (C) head frontal view.

FIGURE 5. Adult male of Fescennia bivitatta dried and mounted; (A) dorsal view, (B-C) frontal view (D) dorso-lateral view and (E) lateral view.

FIGURE 6. SEM photographs of Fescennia bivittata clypeus (A–D) and thorax (E–F).

FIGURE 7. SEM photographs of Fescennia bivittata head, highlighting sensory structures on vertex (A–B), frons (C–E) and antennae (F–L).

FIGURE 8. Fescennia bivitatta hindleg (A), tibial apex (B) and tarsomeres (C–D).

FIGURE 9. Fescennia bivitatta forewing venation.

FIGURE 10. Fescennia bivitatta hindwing venation.

FIGURE 11. Fescennnia bivittata SEM photographs: (A) Tegmen costal margin with sensory structures,(B) jugal lobe of hind wing relative to body, dorsal view, (C) lateral view, (D) jugal lobe position on hind wing, (E) tip of stridulatory plate and (F) stridulatory plate, ventral view.

FIGURE 12. Fescennia bivitatta male terminalia; (A) lateral view, (B) ventral view, (C) dorsal view, (D) lateral view of gonostylus and (E) right lateral view of dissected medioventral process of pygofer.

FIGURE 13. Fescennnia bivittata male, SEM photographs; (A–B) abdomen and terminalia lateral view, (C) anal segement lateral view, (D) pygofer and gonostylus lateral view, (E–F) pygofer and gonostyli ventral view.

FIGURE 14. Fescennia bivitatta aedeagus; (A) right lateral view, (B) left lateral view, (C) dorsal view and (D) ventral view.

FIGURE 15. Fescennia bivitatta aedeagus line art; (A) right lateral view, (B) left lateral view, (C) dorsal view and (D) ventral view.

FIGURE 16. Specimen of Fescennia bivitatta from Arizona State University Collection.