Triatoma phyllosoma

Rengifo-Correa, Laura, Téllez-Rendón, Juan Luis, Esteban, Lyda, Huerta, Herón & Morrone, Juan J., 2021, The Triatoma phyllosoma species group (Hemiptera: Reduviidae: Triatominae), vectors of Chagas disease: Diagnoses and a key to the species, Zootaxa 5023 (3), pp. 335-365 : 359-360

Key to the species of the Triatoma phyllosoma species group

1 Pronotum with humeral angles acute ( Fig. 5C–E ).................................................... T. mexicana

- Pronotum with humeral angles rounded.................................................................... 2

2 Size less than 25 mm; abdomen not strongly widened........................................................ 3

- Size 25 mm or more; most species with strongly widened abdomen ( Figs. 3A, B , 5A, B, F , 6A, B )..................... 9

3 Pronotum with red or yellowish markings in form of narrow band on collar on anterolateral angles and sides of pronotum, and on humeri and some portions along hind border of pronotum ( Fig. 6D )................................ .. T. sanguisuga

- Pronotum without light markings, at most humeral area faintly lighter.............................................4

4 Synthlipsis two-thirds narrower than eye; postocular region two-thirds shorter than eye length; very large eyes in dorsal view ( Fig. 3C ).................................................................................. T. brailovskyi

- Synthlipsis wider than eye; postocular region subequal to eye length; regular sized eyes in dorsal view ( Fig. 4A–C, E–F ).. 5

5 Neck uniformly dark ( Fig. 4C ); posterior lobe of pronotum brownish or piceous, distinctly lighter than anterior lobe................................................................................................ T. gomeznunezi

- Neck with 1+1 lateral reddish or yellow spots ( Fig. 4B ); pronotum uniformly dark.................................. 6

6 Size less than 23 mm; pronotum without lateral tubercles; fore femora relatively stout, about six times as long as wide; base of hemelytra only slightly lighter than remainder; connexival segments dorsally and ventrally almost entirely dark, with barely visible reddish markings in shape of incomplete narrow band along hind border of segments, extending onto intersegmental sutures ( Fig. 4E, F )........................................................................... .. T. indictiva

- Size 23 mm or more; pronotum with lateral tubercles; fore femora relatively slender, from eight to nine times as long as wide; base of hemelytra conspicuously light colored; connexival segments with large yellow or orange-yellow markings adjacent to posterior intersegmental suture ( Figs. 3D–F , 4A, B )........................................................... 7

7 Clavus smoky brown apically; dark markings of connexival segments band-like shaped, with inner margin adjacent to connexival suture ( Fig. 4A, B ).................................................................... T. gerstaeckeri (part)

- Clavus yellow to orange yellow apically; dark markings of connexival segments dot-like shaped, with inner margin separated to connexival suture ( Fig. 3D )............................................................................8

8 Venter largely light yellow, except dark pygophore ( Fig. 7B ); connections between each segment of labium with a light yellow annulus, conspicuously contrasting with surrounding tegument ( Fig. 1B )................... T. huehuetenanguensis (part)

- Venter largely piceous or black, except yellow to orange yellow area adjacent to connexival suture ( Figs. 2A , 7A ); connections between each segment of labium concolorous with labium, or at most slightly lighter than surrounding tegument ( Fig. 2A )........................................................................................ T. dimidiata (part)

9 Head and thorax with abundant pilosity ( Figs. 2D , 3A , 5B ); first antennal segment attaining or surpassing level of apex of clypeus ( Figs. 3A , 6A ); spongy fossulae absent on fore and mid tibiae of both sexes............................... 10

- Head and thorax appearing glabrous dorsally; first antennal segment rarely attaining but not projecting beyond level of apex of clypeus ( Fig. 3D ); spongy fossulae present on fore and mid tibiae of males ( Fig. 2E )............................... 15

10 Posterior lobe of pronotum extensively orange-yellow; corium never yellowish white, instead, corium mainly dark brown to black, with one large subtriangular basal and one irregularly shaped subapical mark orange-red ( Fig. 6B )....... T. picturata

- Posterior lobe of pronotum uniformly piceous or black without markings, at most humeral area faintly lighter; corium extensively yellowish white, dark brown, or dark brown with one large subtriangular basal and one irregularly shaped subapical mark orange-red ( Figs. 3A , 5F ).............................................................................. 11

11 Corium with long, delicate, suberect hairs about 0.3 mm or longer ( Fig. 2C )...................................... 12

- Corium with short, slightly decumbent or adpressed setae shorter than 0.3 mm long ( Fig. 2B )........................ 13

12 Hemelytra short, not extending beyond urotergite VI; width of eye nearly half as wide as the synthlipsis or even smaller ( Fig. 6A )...................................................................................... T. phyllosoma

- Hemelytra long, extending or almost extending to apex of abdomen; width of eye over half as wide as the synthlipsis ( Fig. 5B )........................................................................................ T. mazzottii

13 Corium extensively yellowish white, narrowly orange at base and black at apex; basal half of clavus dark, apical half yellowish white ( Fig. 5F )............................................................................ T. pallidipennis

- Corium without extensive white area, largely black, with yellow or orange-red markings basally and subapically of variable size; clavus uniformly dark, or basal half dark and apical half smoky brown ( Figs. 3A , 5A ).......................... 14

14 Hemelytra short, not extending beyond urotergite VI; clavus with basal half dark and apical half smoky brown; corium uniformly dark or base of corium only slightly lighter than remainder and small yellow or orange-red mark subapically; pronotum with erect setae about 0.5 mm long ( Fig. 3A ).......................................................... T. bassolsae

- Hemelytra long, extending or almost extending to apex of abdomen; clavus uniformely dark; corium with large yellow or orange-red markings basally and subapically; pronotum with stiff setae from very short (± 0.1 mm) and adpressed to longer (up to 0.3 mm) and semierect ( Fig. 5A )............................................................. T. longipennis

15 Corium entirely piceous; connexivum along outer margin with narrow percurrent orange-red band, wider ventrally than on dorsum ( Fig. 6C ).............................................................................. T. recurva

- Corium with light markings; connexivum with different color pattern........................................... 16

16 Connexivum dorsally and ventrally uniformly dark, or each segment with very small light colored spot at junction of intersegmental suture with outer border ( Fig. 4D )..................................................... T. hegneri

- Connexivum with more prominent light-colored markings dorsally and ventrally.................................. 17

17 Dark markings of connexival segments larger than orange-yellow markings; clavus smoky brown apically; venter dark brown to black ( Fig. 4A, B ).................................................................... T. gerstaeckeri (part)

- Dark markings of connexival segments smaller than orange-yellow markings; clavus yellow to orange yellow apically ( Fig. 3D ); venter uniformly light yellow, except dark pygophore, if extensively dark brown to black, then coloration of margin of venter adjacent to connexival suture yellow to orange yellow ( Fig. 2A )...........................................18

18 Venter largely light yellow, except dark pygophore ( Fig. 7B ); connections between each segment of the labium with a light yellow annulus, conspicuously contrasting with surrounding tegument ( Fig. 1B )............. T. huehuetenanguensis (part)

- Venter largely piceous or black, except yellow to orange yellow area adjacent to connexival suture ( Figs. 2A , 7A, C ); connections between each segment of the labium concolorous with labium, or at most slightly lighter than surrounding tegument ( Fig. 2A ) .................................................................................................. 19

19 Membrane of hemelytra almost as pale as corium; pygophore almost round, as long as wide ( Fig. 7C ); postocular portion of head with sides subparallel ( Fig. 1A )................................................................ T. mopan

- Membrane of hemelytra distinctly darker than corium ( Figs. 3D ), rarely almost as pale as corium ( Fig. 3B ); pygophore ovoid, longer than wide ( Figs. 2A , 7A ); postocular portion of head rounded laterally ( Fig. 3D–F ).............. T. dimidiata (part)

Figures

FIGURE 1. Morphology of Triatoma. A, Head of T. mopan, dorsal view (based on Dorn et al., 2018); B, head of T. huehuetenanguensis, ventral view (based on Lima-Cordón et al., 2019); C, pronotum and scutellum of Triatoma, dorsal view; D, abdomen of Triatoma, dorsal view; E, abdomen of T. mopan, ventral view.

FIGURE 2. Morphology of Triatoma. A, male of T. dimidiata, ventral view; B, corium of T. longipennis, dorsal view; C, corium of T. mazzottii, dorsal view; D, pronotum of T. mazzottii, lateral view; E, spongy fossulae of T. dimidiata.

FIGURE 3. Triatoma spp. A, B, T. bassolsae; C, T. brailovskyi; D, E, F T. dimidiata (3B courtesy of E. Barrera-Vargas and 3C courtesy of C. Dale).

FIGURE 4. Triatoma spp. A, B, T. gerstaeckeri; C, T. gomeznunezi; D, T. hegneri; E, F, T. indictiva (4C and D courtesy of C. Dale, 4E, F courtesy of E. Barrera-Vargas).

FIGURE 5. Triatoma spp. A, T. longipennis; B, T. mazzottii; C, D, E. T. mexicana. F, T. pallidipennis.

FIGURE 6. Triatoma spp. A, T. phyllosoma; B, T. picturata; C, T. recurva; D, T. sanguisuga (6D courtesy of C. Dale).

FIGURE 7. Pygophore of Triatoma spp., ventral view. A, T. dimidiata; B, T. huehuetenanguensis; C, T. mopan. Credits of B, Lima-Cordón et al. 2019; C, Dorn et al. 2018.