Trichoprosopon mixtli Rivera-García, Mendez-Andrade & Ibáñez-Bernal, 2023

Rivera-García, Karina D., Mendez-Andrade, Alejandro & Ibáñez-Bernal, Sergio, 2023, Trichoprosopon mixtli sp. nov., a new sabethine species (Diptera: Culicidae) from a Mexican cloud forest, with an assessment of the genus and keys for the identification of known species, Zootaxa 5254 (1), pp. 94-116 : 98-110

Trichoprosopon mixtli Rivera-García, Mendez-Andrade & Ibáñez-Bernal , sp. nov.

( Figs 3–12 )

Diagnosis. Adult female: Maxillary palpus about 0.16 proboscis length; proboscis as long as forefemur. Postpronotum with brown scales with golden-violaceous reflections; midtarsomeres 2–4 with white scales; hindtarsomeres 4 and 5 white-scaled; upper calypter with an incomplete row of setae ( Figs 3–6 ). Female genitalia: Insula pyriform; upper vaginal sclerite small. Tergum IX with interlobar space shallow V-shape ( Figs 7 , 8 ). Male genitalia: Tergum IX with a deep interlobar space, with 4–6 long foliaceus setae on each lobe. Gonocoxite about 3 times longer than wide; basal mesal lobe below midlength of gonocoxite, setae do not extend beyond apex of gonocoxite. Gonostylus about 0.5 gonocoxite length; gonostylar claw less than 0.25 gonostylus length. Proctiger with 8–14 cercal setae, paraproct with 2 or 3 apical teeth (unusually 3). Aedeagus elongate, oval, pointed at apex ( Figs 9 , 10 ). Pupa: Seta 1-II usually single, sometimes forked at midlength; seta 5-II–IV short, never longer than segment length. Paddle shorter than segment VIII length, without spicules at apex ( Fig. 11 ). Larva: Mandible large, well developed, with 6 sclerotized teeth; maxilla without a terminal tooth; dorsomentum with 6–9 teeth on each side; seta 8-C single. Abdominal segment VIII without comb; seta 5-VIII single, strong, inserted in a small tubercle. Siphon without pecten; siphon index 1.5–2.0. Saddle incomplete, with spicules more evident distally ( Fig. 12 ).

Female, holotype ( Figs 3–6 ). Head: Occiput and vertex covered with silver scales, with bluish or slightly purplish reflections, occiput with a row of erect scales ( Fig. 4a ); ocular line with 11 evenly separated setae, interocular setae large, convergent. Antenna about 0.75 forefemur length. Clypeus dark brown, with strong setae. Maxillary palpus about 0.16 proboscis length, dark-scaled with bluish-greenish reflections. Proboscis as long as forefemur, sometimes slightly longer than forefemur, with dark brown scales with bluish reflections ( Fig. 4a ). Thorax: Integument of antepronotum light brown, covered with brown scales with conspicuous silvery reflections, less evident posteriorly, with 6 setae ( Figs 3a , 4 ). Postpronotum covered with brown scales with golden-violaceous reflections ( Figs 3a , 4 ). Integument of scutum dark brown, covered with light brown scales with grayish reflections ( Fig. 3b ). Scutellum trilobed, covered with silver scales with bluish reflections, each lobe with 4 strong setae distally ( Fig. 3b ). Mesopostnotum without or with 1–12 (mode = 4) hyaline scales and a group of 2–8 (mode = 6,7) setae posteriorly ( Fig. 5a ). Postspiracular area, integument of mesokatepisternum and mesanepimeron light brown, covered with silver scales ( Fig. 4b ). Halter: Dark brown with golden reflections. Wing: Scales from proximal 0.5 of costa and radial veins with bluish reflections; upper calypter with an incomplete row of setae ( Fig. 5b ). Legs: Coxae covered with silver scales, mainly on basal 0.5. Trochanters with golden scales. All femora and tibiae dark-scaled, scales with purplish or blue reflections, more conspicuous dorsally (these reflections not evident ventrally). Foreleg dark-scaled; midleg with femur and tibia dark-scaled, midtarsomere 1 dark-scaled, midtarsomeres 2–4 with white scales (some specimens with midtarsomere 4 dark-scaled at apex), midtarsomere 5 usually entirely dark-scaled (some specimens with a few white scales basally) ( Fig. 6a ); hindfemur dark-scaled, hindtibia dark-scaled with a basal white spot, mainly on ventral surface ( Fig. 6b ), hindtarsomeres 1–3 dark-scaled, hindtarsomeres 4 and 5 with white scales ( Fig. 6c ). Abdomen: All terga covered with dark scales with bluish-greenish reflections, lateral margins with golden scales ( Fig. 3b ); sternal scales not observed because of collapsed abdomen.

Female genitalia ( Figs 7 , 8 ). Before dissection and mounting on slides: As in figure 7a. Segment VIII: Barely retracted into segment VII; intersegmental membrane between segments VII and VIII very short, about 0.10 length of segment VIII ( Fig. 7a ). Tergum VIII: Surface covered totally with iridescent-blue scales and some large black setae along lateral and posterior margins, those on posterior margin largest and more numerous ( Fig. 7b ); tergum VIII covering lateral portion of sternum VIII ( Fig. 7a ). Sternum VIII: Nearly quadrangular, lateral margins parallel, distal margin shallowly concave at middle and rounded lobed corners, with all exposed surface covered with scales, iridescent-blue in an inverted V-shaped patch at middle, pale gold scales at sides; triangular patch of blue scales also with evenly spaced large black setae, those on posterior margin largest ( Fig. 7c ). Segment IX: Completely retracted into segment VIII ( Fig. 7a ); postgenital lobe and cerci hardly exposed, apex of lobe not exceeding apex of cerci ( Fig. 7a, d ).

Genitalia dissected and mounted in slides: Tergum VIII: Proximal 0.10 retracted into segment VII; surface of tergum VIII covered with scales, except 0.10 of proximal margin, and with several long stout setae along distal margin; tergum VIII index 0.66; VIII-Te/IX-Te index 2.59; length 0.35 mm; width 0.75 mm ( Fig. 7b ). Sternum VIII: Covered with scales, those at middle dark (iridescent blue) in a triangular patch which also has strong evenly spaced setae, rest of scales pale (pale golden); width greater than length; apex very gently concave, but with a convex median emargination covered with microtrichia and with moderately long setae on apical margin; sternum VIII index 0.74; length 0.50; width 0.70 ( Fig. 7c ). Tergum IX: Crescent shaped; covered with minute spicules; apex bilobed separated by a V-shaped interlobar space, each lobe with 3 or 4 stout moderately long setae; tergum IX index 0.41; length 0.13 mm; width 0.33 mm ( Figs 7d , 8 ). Insula: Small, pyriform ( Fig. 8 ). Lower vaginal lip: A somewhat sclerotized transversal rod ( Fig. 8 ). Upper vaginal lip: Covered with short spicules. Upper vaginal sclerite: Small and narrow, without defined shape ( Fig. 8 ). Spermathecal eminence: Posterior 0.75 somewhat ovoid, basal area narrower; few short, simple spermathecal eminence spicules on basolateral areas ( Fig. 8 ). Spermathecal capsules: One large and 2 medium, heavily pigmented, spherical, with few to several small spermathecal capsule pores near orifice ( Figs 7d , 8 ). Accessory gland duct: Basal area not pigmented. Postgenital lobe: Covered with short spicules, posterior margin with moderately long setae; apex somewhat bilobed with median emargination; ventral surface with about 7 longer setae distally on each side, about 14 total long setae but numerous small setae on all surface; ventral length 0.10 ( Figs 7d , 8 ). Cercus: Flat, eggplant-shaped (elongated oval), covered with short to moderately long spicules; apex wide, rounded; mesal margin slightly concave on basal 0.50; cercus index 2.5; Ce/dorsal PGL index 1.06; length 0.18 mm; width 0.07 mm ( Figs 7d , 8 ).

Male. Similar to female. Legs: White scales only dorsally on midtarsus; midtarsomere 1 dark-scaled; midtarsomeres 2 and 3 covered with white scales; midtarsomere 4 with white scales on basal 0.50 or 0.75, covered entirely with white scales in 2 specimens examined; midtarsomere 5 dark-scaled.

Male genitalia ( Figs 9 , 10 ). Tergum IX with deep interlobar U-shaped space, distance between lobes similar to lobe width, each lobe with 4–6 (mode = 5,6) long, foliaceus, pointed setae that do not reach basal mesal lobe of gonocoxite ( Fig. 9a, c ). Gonocoxite long, about 3 times longer than wider, with a slightly pointed basal mesal lobe below midlength, with 4–7 (mode = 5) long and conspicuous setae that do not extend beyond apex of gonocoxite ( Fig. 9a ). Gonostylus shorter than gonocoxite (about 0.5 gonocoxite length), with basal portion slightly expanded; gonostylar claw short, less than 0.25 gonostylus length and less than 0.13 gonocoxite length, bifurcate at apex ( Fig. 9a, b ). Proctiger with 8–14 (mode = 10) cercal setae, paraproct slender, strongly sclerotized laterally and apically, with 2 apical teeth (2 specimens with 1 additional small tooth) ( Figs 9a , 10a ). Aedeagus long, oval, pointed at apex; paramere 3 times longer than wide, pointed at apex ( Fig. 10b ).

Pupa ( Fig. 11 ). Chaetotaxy in Table 2 . Cephalothorax: Lightly tanned.Setae 1,11-CT long, conspicuous, strongly developed, especially 1-CT ( Fig. 11a, b ). Trumpet: Relatively short, conical, more tanned than cephalothorax; length ♀ 0.41–0.51 (m = 0.46; sd = 0.03; n = 8), ♁ 0.40–0.50 (m = 0.45; sd = 0.03; n = 12); width ♀ 0.18–0.22 (m = 0.19; sd = 0.01; n = 8), ♁ 0.15–0.22 (m = 0.19; sd = 0.01; n = 12); trumpet index ♀ 2.15–2.77 (m = 2.34; sd = 0.21; n = 8), ♁ 2.0–2.8 (m = 2.39; sd = 0.29; n = 12); pinna ♀ 0.02–0.08 (m = 0.04; sd = 0.02; n = 8), ♁ 0.02–0.06 (m = 0.03; sd = 0.01; n = 12); meatus ♀ 0.38–0.49 (m = 0.42; sd = 0.03; n = 8), ♁ 0.37–0.46 (m = 0.41; sd = 0.02; n = 12) ( Fig. 11a ). Abdomen: Lightly tanned, without conspicuous dark areas. Length ♀ 4.58–5.7 (m = 4.99; sd = 0.38; n = 8), ♁ 4.24–4.8 (m = 4.6; sd = 0.17; n = 12) ( Fig. 11b ). Seta 1-I fanlike with dendritic branches, usually with 2 basal and 23 terminal branches; setae 3-I, 1,3-II and 1-III long, conspicuous, extending beyond posterior margin of following tergum; seta 6-II–IV conspicuous, strongly developed; seta 9-VII,VIII fanlike, strong with aciculate branches. Paddle: Short, slightly longer than male genital lobe, about 2 times female genital lobe length, usually shorter or as long as abdominal segment VIII; margin without spicules or any other ornamentation; buttress inconspicuous; midrib slightly conspicuous, extending to margin, inner part smaller than outer part, inner margin shorter than outer margin; apex without setae; length ♀ 0.53–0.62 (m = 0.58; sd = 0.03; n = 8), ♁ 0.49–0.63 (m = 0.54; sd = 0.03; n = 12); width ♀ 0.46–0.55 (m = 0.51; sd = 0.03; n = 8), ♁ 0.45–0.60 (m = 0.50; sd = 0.03; n = 12); paddle index ♀ 1.09–1.24 (m = 1.13; sd = 0.05; n = 8), ♁ 0.86–1.22 (m = 1.08; sd = 0.11; n = 12) ( Fig. 8b ). Genital lobe: Lightly tanned, without spicules; length ♀ 0.27–0.32 (m = 0.29; sd = 0.01; n = 8), ♁ 0.49–0.58 (m = 0.52; sd = 0.02; n = 12) ( Fig. 11b ).

Larva, fourth-instar ( Fig. 12 ). Chaetotaxy in Table 3 . Head: Slightly subquadrate, with rounded lateral margins. Mandible large, with 4 small teeth, a fifth subapical large and conspicuous tooth and a sixth apical tooth smaller than subapical tooth; maxilla small, toothless, with fused maxillary palpus extending beyond apex of maxillary body; dorsomentum usually with 8 teeth on each side and 1 in middle (6–9 on each side and 14–19 in total) ( Fig. 12c ). Antenna: Short, about 0.25 length of head, without spicules or other ornamentation; seta 1-A preapical, single ( Fig. 12b ). Thorax: Setae 1,4–7,9,10,12-P, 5–6,9,10,12-M and 7,9,10,12,13-T strong, long, conspicuous, 13-T slightly spinulate; setae 0,4-P, 5–7-P and 5,6-M inserted on plates; setae 9,10,12-P,M inserted on tubercles; setae 7,9–13-T inserted on a U-shaped plate with 7 and 13 at opposite ends ( Fig. 12a ). Abdomen: Setae 6-I–VI, 7-I–IV and 1-II–VII strong, long, conspicuous, inserted on tubercles ( Fig. 12a ). Abdominal segment VIII: Without comb; seta 3-VIII very large, with aciculate branches, seta 5-VIII always single, strong, conspicuous, inserted on a sclerotized tubercle ( Fig. 12d ). Abdominal segment X: Saddle incomplete, with dorsoposterior spicules, larger in distal region ( Fig. 12d ). Anal papillae: Long, about 3 times saddle length ( Fig. 12d ). Siphon: Without pecten, with few observable spicules; seta 1a-S as long as diameter of siphon at its insertion, usually with 10 aciculate branches; seta 1b-S short but evident, usually with 2 branches; siphon index 1.5–2.0.

Etymology. The name “ mixtli ” is derived from the Nahuatl language of the ancient native Mexican population of the region. The specific name as a noun means “cloud” and as an adjective it means “cloudy”, referring to the cloud forest in which this species was found. The name of the species is regarded here to be a noun in apposition to the generic name of Trichoprosopon , which is neuter.

Bionomics. Immature stages of the new species were found with Shannoniana moralesi ( Dyar & Knab, 1919) in flower bracts of H. bourgaeana , located in full shade. Larvae and pupae were more abundant during months with higher rainfall.

Distribution. Presently, only known from the type locality in Veracruz, Mexico.

Material examined. HOLOTYPE: ♀ mounted on entomological pin, with associated larval and pupal exuviae mounted on a microscope slide, MEXICO: Veracruz, Xalapa, Área Natural Protegida Estatal “Francisco Javier Clavijero”, Santuario del Bosque de Niebla , Instituto de Ecología , A.C., INECOL (19° 30′ 45″ N, 96° 56′ 36″ W), altitude 1,315 m, direct collection of immatures stages from water in flower bracts of Heliconia bourgaeana, K. D. Rivera-García col., 10 October 2019 . Allotype: ♁ mounted on entomological pin, with dissected genitalia (preserved in micro-vial on the respective entomological pin), larval and pupal exuviae mounted on a microscope slide. Paratypes: Same data as holotype , 7♀, 11♁, 18 pupal exuviae, 6 larval exuviae and 7 fourth-instar larvae, 10 October 2019. 3 fourth-instar larvae, 29 September 2021. 4♀ with pupal exuviae, 1 fourth-instar larva, 06 October 2021, associated with a larva of Sh. moralesi ; 10♀, 11♁, 21 pupal exuviae, 15 larval exuviae, 7 fourth-instar larvae, 03 May 2022. Specimens are deposited in the Colección Entomológica del Instituto de Ecología, A.C. ( IEXA), Xalapa , Veracruz, Mexico . Other material examined: Females (n = 10) and male genitalia (n = 3) of Tr. digitatum of Viveros-Santos et al. (2022), which are deposited in IEXA-INECOL.

Figures

FIGURE 3. Adult female of Trichoprosopon mixtli, holotype. a, Lateral view; b, dorsal view. Fe-I, forefemur; Ta-III, hindtarsus; Ti-II, midtibia; Ti-III, hindtibia.

FIGURE 4. Adult female of Trichoprosopon mixtli, holotype. a, Head and thorax, anterodorsal view; b, head and thorax, lateral view. Ap, antepronotum; Ppn, postpronotum; V, vertex.

FIGURE 5. Adult female of Trichoprosopon mixtli, holotype. a, Mesopostnotum, dorsal view; b, wing, upper calypter.

FIGURE 6. Adult female of Trichoprosopon mixtli, holotype. a, Midtarsus; b, hindtibia; c, hindtarsus. Ta-II, midtarsus; Ta-III, hindtarsus.

FIGURE 7. Female genitalia of Trichoprosopon mixtli. a, Ventral view; b, tergum VIII; c, sternum VIII; d, cercus and spermathecal capsules. Ce, cercus; PGL, postgenital lobe; SCa, spermathecal capsule; VIII-S, sternum VIII; VIII-Te, tergum VIII; IX-Te, tergum IX.

FIGURE 8. Female genitalia of Trichoprosopon mixtli, ventral view. Ce, cercus; I, insula; LVL, lower vaginal lip; PGL, postgenital lobe; SCa, spermathecal capsule; SE, spermathecal eminence; UVL, upper vaginal lip; UVS, upper vaginal sclerite; IX-Te, tergum IX; X-Te, tergum X.

FIGURE 9. Male genitalia of Trichoprosopon mixtli, allotype. a, Ventral view (post-rotation); b, gonostylus; c, tergum IX. BML, basal mesal lobe; Gc, gonocoxite; GC, gonostylar claw; Gs, gonostylus; Ppr, paraproct; Pr, proctiger; IX-Te, tergum IX; IX-TS, setae of tergum IX; IX-TL, tergum IX lobe.

FIGURE 10. Male genitalia of Trichoprosopon mixtli, allotype. a, Paraproct; b, aedeagus. Ae, aedeagus; BML, basal mesal lobe; CSe, cercal setae; Ppr, paraproct; PprT, paraproct teeth; Pr, proctiger.

FIGURE 11. Pupa of Trichoprosopon mixtli. a, Cephalothorax; b, abdomen. CT, cephalothorax; GL, genital lobe; Pa, paddle; I–IX, abdominal segments I–IX; 0–14, setal numbers for specified areas.

FIGURE 12. Fourth-instar larva of Trichoprosopon mixtli. a, Thorax and abdomen; b, head; c, mandible, maxilla and dorsomentum; d, abdominal segments VII–X and siphon. A, antenna; C, cranium; Dm, dorsomentum; M, mesothorax; Pa, paddle; P, prothorax; T, metathorax; S, siphon; Sa, saddle; I–X, abdominal segments I–X; 0–15, setal numbers for specified areas.

Tables

TABLE 2. Range (mode) of branches for pupal setae of Trichoprosopon mixtli. (+) Number of basal branches; (°) number of terminal branches (forked seta); (*) fanlike setae with aciculate branches in the basal portion.

Seta	Cephalothorax	Abdominal segments
no.	CT	I	II	III	IV	V	VI	VII	VIII
0	–	–	1	1	1	1	1	1	1
1	1–3(2)	2–5(2)+, 16–42(23)°	1–3(1)	1,2(1)	1,2(1)	1,2(1)	1,2(1)	1	–
2	1–4(2)	1	1	1	1,2(1)	1	1,2(1)	1	–
3	2–5(3)	1,2(1)	1	2–5(3)	1–5(3)	1,2(1)	1	1,2(1)	–
4	1–5(2)	1–4(1)	2–6(3)	1–4(2)	1–3(2)	1–5(2)	1–5(4)	2–6(3)	1
5	1–5(2)	2–9(4)	1–4(2)	1–3(1)	1–3(1)	1–5(3)	1,2(1)	1	–
6	1–3(1)	1–5(2)	1–5(3)	1–4(3)	1–7(2)	1–6(2)	1–3(1)	1–4(2)	–
7	1–4(1)	1–5(3)	2–7(3)	2–10(5)	2–8(3)	2–6(5)	1–4(2)	1–3(1)	–
8	1–4(2)	–	–	1–4(2)	1–4(3)	1–5(2)	2–5(4)	2–8(4)	–
9	1,2(1)	1,2(1)	1	1	1	1	1	6–18(12)*	14–28(19)*
10	1–3(1)	–	–	1,2(1)	1–3(1)	1,2(1)	1,2(1)	1	–
11	1,2(1)	–	1–3(2)	1–4(2)	1–4(2)	1–3(2)	1–4(2)	1–4(2)	–
12	1–4(2)	–	–	–	–	–	–	–	–
14	–	–	–	–	–	–	–	–	1