Micrutalis Fowler, 1895

McKamey, Stuart H. & Wallner, Adam M., 2022, The immatures of the New World treehopper tribes Acutalini Fowler and Micrutalini Haupt (Hemiptera, Membracidae, Smiliinae), ZooKeys 1136, pp. 187-208 : 187

Micrutalis Fowler

Figs 23-28 , 29, 30 , 31-34 , 35-37 , 38-43

Nymph diagnosis.

Fifth instar body length 3.0-3.5 mm; head and premetopidium lacking enlarged chalazae or scoli, postmetopidium with short scoli or enlarged chalazae; mesonotum to abdominal segment IX with small paired scoli; abdominal terga with 1 or 2 well-developed rows of enlarged chalazae or scoli; body densely setose, triangular in cross-section, not vertically compressed; abdomen lacking ventrolateral lamellae; wing pad costal margin linear or almost so; fused portion of abdominal segment IX directed posteriorly.

Nymph description.

Overall body. Fifth instar length 3.0-3.5 mm. Cross-section subtriangular (except laterally compressed in M. dubia Fowler); chalazae on thorax and abdomen usually dense; chalazal setae long; no parts of body covered with wax-like substance; dorsal contour of abdomen in lateral view linear; scoli parallel; overall body in dorsal view elongate. Head. Lacking scoli; dorsal or anterior rounded protuberances absent; chalazal bases long-stalked (except tuberculate in M. dubia ); chalazal setae simple, needlelike (except narrowly peltate in M. dubia ) compound eye surface with setae; enlarged chalazae present or absent between eyes; setae of frontoclypeus scattered and sparse (except dense in M. callangensis ); enlarged chalazae present in front of ventral margin of eye; enlarged chalazae present adjacent to central or dorsal margin of eye; frons extending over central margin of eye. Prothorax. Premetopidium lacking scoli; postmetopidium without dorsal paired structures or, if present (Fig. 33 ), with enlarged chalazae or small scoli directed dorsoposteriorly or dorsally then abruptly posteriorly; posterior extension of pronotum not surpassing anterior margin of metanotum, apex narrowly convex or acute; pronotal lateral margin rounded; postmetopidial scoli, if present, length about 2-4 × basal width; metopidial sulcus not incised. Mesothorax. Dorsal structures consisting of paired scoli; scoli bearing stalked chalazae; scoli directed dorsoposteriorly or dorsally then abruptly posteriorly (except bluntly rounded in M. callangensis ); forewing pad anterior costal margin form straight (except weakly sinuate in M. dubia ); forewing pad surface chalazae sparse and with short setae (except densely covered in long setae in M. callangensis ); scoli length about 2-4 × basal width (except subequal to basal width in M. callangensis ); anterior basal side of scoli lacking cluster of enlarged chalazae; forewing pad costal chalazae present only on base of costal margin (except along enture costal margin M. callangensis ); lateral rows of abdomen with most medial row extending onto meso- and metathorax. Metathorax. Dorsal structures consisting of paired scoli; scoli bearing short-stalked chalazae; scoli directed dorsoposteriorly or dorsally then abruptly posteriorly; dorsal scoli length about 2-4 × basal width (except subequal to basal width in M. callangensis ). Legs. Tibia with chalazae present on both lateral margins and dorsal surface; prothoracic tibia form subcylindrical; metathoracic tarsal length subequal to pro- and mesothoracic tarsal length; all first tarsomeres distinctly shorter than second tarsomeres. Abdomen. Terga III-VIII ventrolateral margins lacking scoli but each with 2 enlarged chalazae (except with a single enlarged chalazae in M. callangensis ); terga III-VIII with dorsal scoli present, subequal in size to each other (2-4 × basal width). directed dorsoposteriorly or dorsally then abruptly posteriorly; terga III-VIII with lateral 1 or 2 rows of enlarged chalazae (Fig. 33 ) or manifested as scoli (in M. callangensis ); abdominal scoli bearing stalked chalazae (except bearing tuberculate chalazae in M. dubia ). Segment IX: distal half tubular in cross-section; dorsal length subequal to length of segment V-VIII (except subequal to combined length of remaining visible abdominal terga in M. callangensis ); preapical dorsal surface irregularly covered with chalazae; dorsal structures at apex consisting of paired scoli; ventral extension subequal to dorsal extension; fused portion of segment IX directed posteriorly and distal to unfused portion; unfused portion distally not bifurcate.

Material examined.

Micrutalis callangensis , 1 adult, 1 nymph, Ecuador: Cañar, Ducur , 25 May 1986, S.H. McKamey leg., lot # 86-0525-4, 86-0525-5 (USNM); Micrutalis undescribed species , 2 adults, 1 nymph, Nicaragua: Leon Finca N.I.L., 8 [October] 1989, J.M. Maes leg., ex Cordia sp. (USNM); M. dubia , 1 adult, 2 nymphs, Venezuela: Ed. Merida, Zona Los Cinaros , 58 km SW Merida, 24 July 1984, S.H. McKamey leg., lot #1008, 1009 (USNM). Micrutalis sp. 2 , 2 adults, 2 nymphs, Ecuador: Loja, Loja, ca 2000 m alt., 30 May 1986, S.H. McKamey leg., lot #86-0530-7, 86-0530-8 (USNM); Micrutalis sp., 1 nymph (unassociated with adults), Mexico: Animal and Plant Health Inspection Service (APHIS) intercept APSCA191974874004 at San Ysidro, California , 15-VII-2019, ex Dysphania ambrosioides (L.) Mosyakin & Clemants ( Amaranthaceae ; commonly known as espazote, Mexican tea, paico, and wormseed) .

Hosts.

The great majority of Micrutalis species lack host information. Nevertheless, there are some host records in the literature and among specimens examined in this study. Nixon and Thompson (1987) reported that M. calva was polyphagous, with adults feeding on wormwood, soapwort, sycamore, redbud, ironweed, alfalfa, ragweed, sunflower, black locust, and honey locust. Nixon and Thompson (1987) also reported that nymphs have been collected on ironweed, ragweed, sunflower, and honey locust ( Gleditsia triacanthos L.); nymphs were collected on ironwood, ragweed, sunflower, and honey locust. The holotype of M. henki Sakakibara (1999b) was collected on Luhea [sic, for Luehea ] seemannii Triana & Planch. Flynn and Wheeler (2016) recorded M. pallens on Anisacanthus thurberi [Torr.] A. Gray, Acanthaceae , but could not identify the Micrutalis species because the nymphs were not reared to adults. Wheeler and Flynn (2021) recorded M. discalis (Walker) from mistletoe ( Phoradendron californicum Nutt., Viscaceae ). The M. dubia from Ecuador in our study was collected on Cordia sp., Boraginaceae . The APHIS intercepted nymph was on Dysphania ambrosioide s (L.) Mosyakin & Clemants ( Amaranthaceae ).

Remarks.

Although Micrutalini adults are distinguished by their wing venation and genitalia, the small size of the fifth instars of Micrutalis sets them apart from most treehoppers. The only New World treehoppers that rival their small size are some Bolbonota Amyot & Serville, Eunusa Fonseca, some Tragopini , Thuridini , Quadrinareini , some Amastris Stål, Centrodontini , Endoiastinae , Deiroderes , Brachytalis Metcalf & Bruner, Brachybelus Stål, and Abelus Stål. Micrutalis nymphs differ from the nymphs of all these small genera in one or more of the features listed above in the diagnosis of Micrutalis . In contrast to nymphs of Micrutalis , Bolbonota nymphs are covered with white wax-like exudate; Eunusa nymphs are covered with erect, stalked scoli and have the segment IX directed dorsally; nymphs of Tragopini , Thuridini , and Quadrinareini lack scoli entirely; Centrodontini and Endoiastinae lack setae, Brachytalis nymphs have the posterior margin of the metathorax mesally lengthened; and Deiroderes and Brachybelus nymphs have ventrolateally flattened abdominal lamellae. The only genus among these for which the nymphs are unknown is Abelus . We presume these resemble those of the closely related Ischnocentrus Stål, which have the costal margin of the wing pad notched. The most unusual Micrutalis species is M. callangensis , with its rounded meso- and metathoracic scoli, and its abdomen with lateral rows manifested as scoli rather than enlarged chalazae, and a proportionately longer segment IX.

Figures

Figures 23 - 28. Micrutalis nymphs 23 M. calva from Allison Park, Allegheny Co, PA, courtesy of John Rosenfeld 24 M. discalis (Walker) on mistletoe from AZ, courtesy of Al Wheeler 25 Micrutalis sp. from Costa Rica ex Miconia calvescens DC (Melastomataceae), courtesy of Kenji Nishida 26 Micrutalis sp. from Leon, Nicaragua, lateral view 27, 28 M. dubia Fowler, from Zona los Cinaros, Merida State, Venezuela, in dorsal and lateral view, respectively.

Figures 29, 30. Micrutalis sp. 2 from Loja, Ecuador in lateral and dorsal view, respectively.

Figures 31 - 34. Micrutalis sp. 31 habitus anterior view 32 detail posterior abdomen in dorsal view 33, 34 habitus in lateral and dorsal views, respectively.

Figures 35 - 37. Micrutalis callangensis Goding in anterior, dorsal, and lateral views, respectively.

Figures 38 - 43. Micrutalis 38 - 40 Micrutalis sp. in anterior, detailed lateral head and portion of pronotum, and detailed abdomen, dorsal view, respectively 41, 42 Micrutalis undescribed sp., adult and nymph from Costa Rica, ex Hamelia patens Jacq. (Rubiaceae), courtesy of Kenji Nishida 43 Micrutalis undescribed sp., adult (upper right) and nymph (lower left, indicated by arrow) from San Juan, Bolivia by © Kozue Kawakami (CC BY).