Dysyncritus Fowler 1895
Creators: name: Evangelista, Olivia
name: Flórez-V, Camilo
name: Sakakibara, Albino M.
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Hemiptera
Membracidae
Dysyncritus

description: Dysyncritus Fowler, 1895
Type-species by monotypy: Dysyncritus intectus Fowler, 1895b:81.
Dysyncritus Fowler, 1895b: 80 [new genus, Pl. VI, Figs. 13 a,b]; Fowler, 1894c:50 [key]; Buckton, 1903a: 108 [key], 149 [listed]; Poulton, 1903a: 280 [camouflage]; Goding, 1926e: 308 [key]; Funkhouser, 1927f: 127, 153 [listed in Darninae as junior synonym of Procyrta Stål]; Goding, 1930b: 12 [key to species, with new taxa from Brazil]; Funkhouser, 1951a: 84 [listed in Darninae as junior synonym of Procyrta Stål]; Metcalf & Wade, 1965a: 645 [catalogued in Darninae, Cymbomorphini]; Deitz, 1975a: 150 [to Heteronotinae]; McKamey, 1998a: 162 [catalogued]; Dietrich et al., 2001a: 215, 228-9 [key to subfamilies and tribes of Membracidae, phylogenetic remarks: misidentified]; Lin et al., 2004a: 402 [phylogenetic remarks: misidentified].
Diagnosis. Vertex flat or slightly convex below ocelli, deflected backwards on lower half; pronotum low, convex dorsally in lateral view, lacking suprahumeral horns, tubercles and spines; in dorsal view, anteriorly round at metopidium, widest between humeral angles, posterior process triangular, tapering towards acute apex in dorsal view; forewings with initial division of vein R as follows: R1 and R s A [R2+3] + R s P [R4+5] (i.e., R1 diverging prior to other R branches), crossveins s, r-m and m-cu 2 present (one each); row III of hind tibia with cucullate setae smaller in comparison to row I and row II, extended through entire length of hind tibia; male abdomen lacking lamellar laterotergites; male genitalia with aedeagus U-shaped, lateral and subgenital plates sheet-like, not inflated; styles robust and elongated, shank well developed.
Description. Color: head, pronotum, and legs variegated brown, ferruginous and yellow. Fore- and hind wings mostly hyaline. Forewings with coriaceous areas opaque, variegated with same colors as pronotum.
Head: triangular, dense and roughly punctate; eyes and ocelli well produced, eyes globose; vertex pentagonal, convex, superior margin arched above ocelli, area below ocelli slightly deflected backwards (not as medially concave as in Allodrilus gen. nov., and some species of Smiliorachis Fairmaire); coronal suture distinct throughout, not conspicuously grooved; ocelli closer to eyes than to each other, located approximately on imaginary line that crosses center of eyes; suprantennal ledges broad, sharply carinate, foliaceous, discreetly curved forwards; frontoclypeus weakly concave, diamond-shaped, about as wide as long, exceeding lower margins of vertex.
Pronotum: low, convex dorsally in lateral view, lacking suprahumeral horns, tubercles and spines; in dorsal view, anteriorly round at metopidium, widest between humeral angles, posterior process triangular, tapering towards acute apex in dorsal view; surface roughly punctured, pits smaller and more numerous near base of metopidium, progressively enlarged towards apex of posterior process; metopidium curved above suprahumeral angles in lateral view; posterior process triangular, gradually tapering to acute apex as seen in lateral and dorsal view.
Wings: forewing membrane with coriaceous, densely punctate area at basal third; veins prominent, with discreet adjacent punctation throughout; R, M and Cu fused at base: R separating shortly after, M and Cu confluent for short distance, diverging at basal third; initial division of R: R1 and R s A [R2+3] + R s P [R4+5] (i.e., R1 diverging prior to other branches of R); crossveins s, r-m and m-cu 2 present (one each); one discoidal cell; M1+2 and M3+4 conspicuously oblique; A1 well marked and elongate, A2 indistinct. Hind wings with one r-m and one m-cu, A1 and A2 confluent pre-apically, diverging at about mid length; jugal lobe well developed, broadly round.
Legs: pro-, meso- and metathoracic legs lacking cucullate setae (except for hind tibia), tibia prismatic, not foliaceous; hind tibia with three rows of cucullate setae, row I and II showing distinctly robust setae, row III with comparatively smaller setae, extended through most of tibia (not reduced in number or absent); surface of hind tibia between rows with minute, densely distributed setae.
Abdomen: abdominal segments lacking conspicuous punctation, dorsal tuberosities or fenestrae; males lacking lamellar laterotergites in segments IV–VII; VIII sternite rectangular. Male genitalia: lateral and subgenital plates sheet-like, not swollen; aedeagus well developed, shaft cylindrical, U-shaped; styles robust with elongated shank, curved laterad, hook-like. Female genitalia not examined.
Distribution. MEXICO (Tabasco: Teapa); GUATEMALA: Alta Verapaz: San Juan Chamelco (listed in Fowler, 1895b); HONDURAS (Yoro: Yoro).
Remarks. Prior to this revision, Dysyncritus included morphologically heterogenous taxa that are not congeneric with the type-species D. intectus Fowler. Therefore, this genus is here treated as monotypic. In fact, some morphological features previously attributed to Dysyncritus are observed in species now classified in Smiliorachis Fairmaire, or in the newly described Allodrilus gen. nov. Dysyncritus is redefined based on the configuration of the head, forewing venation, chaetotaxy of hind legs, and male genitalia; these characters will be briefly discussed in order to clarify previous misinterpretations. The overall shape of the vertex, compared to other heteronotines, is convex as opposed to medially concave. In the latter case, the vertex is depressed below ocelli, whereas the frontoclypeus and suprantennal ledges are pressed down anteriorly, and curved forwards posteriorly (a conspicuous feature in A. alboferrugineus sp. nov. and A. colombiensis sp. nov., Figs. 38–39). In D. intectus, the vertex is nearly flat, deflected backwards below ocelli, the lower margins of the suprantennal ledges are slightly directed forwards, and the frontoclypeus is weakly scoop-shaped (sensu Dietrich et al., 2001) (Fig. 36). The forewing venation of D. intectus also shows a peculiar arrangement: the R vein initially separates into R1 and R s A + R s P (the major branches of radial sector—anterior [R s A] and posterior [R s P]—in most membracids constituted of veins R2+3 and R4+5, respectively) (Fig. 3). This condition is newly reported in heteronotines, and was to date exclusively seen in D. intectus, and the type-specimen of Rhexia pallescens Fabricius (Evangelista, personal observation). In the remaining heteronotine genera (other species of Rhexia included), R1 is confluent with R s A for a short distance, and branches out after the first bifurcation of R (i.e., R1+R s A and R s P) (Fig. 4). The left forewing of the paralectotype male of D. intectus (shown in Fig. 3, indicated by an asterisk) is, however, anomalous with respect to the pre-apical separation of veins M3 and M4, which are entirely confluent in other examined specimens.
Another diagnostic character of Dysyncritus is the chaetotaxy of hind legs. In the family-level phylogeny inferred by Dietrich et al. (2001a), the state ‘reduced or absent hind tibial setal row III’—recovered as a unique synapomorphy supporting Membracinae—was also scored to a terminal taxon identified as D. intectus. Given their set of morphological characters, the placement of Dysyncritus would require one extra step, according to a parsimony analysis. Based on these results, the authors suggested that either Membracinae was phylogenetically related to Heteronotinae, or Dysyncritus was misplaced to subfamily level, rendering D. intectus the status of ‘morphological intermediate’ (Dietrich et al., 2001a; Lin et al., 2004a). Examination of the type series of D. intectus revealed conspicuous cucullate setae in hind tibial row III along most of the tibia; setal rows I and III consist of much larger spines, similar to those observed in several membracines (Fig. 69). The taxonomic placement of D. intectus in Heteronotinae is confirmed by the following set of characters: (a) pronotum not concealing wings in repose; (b) forewings with one cross-vein s, one r-m, and one m-cu (m-cu 2); (c) tibia prismatic; and (d) abdomen lacking conspicuous punctation or dorsal tuberosities. The misidentified exemplar in Dietrich et al. ’s analysis (not examined in this study) possibly belongs in Allodrilus gen. nov or Smiliorachis, which suggests that the reduction of hind tibial setal row III could have occurred independently in unrelated treehopper lineages. Male genitalic structures in D. intectus are much less elaborate than similar genera in Heteronotinae, and resemble those observed in many other membracid groups: sheet-like subgenital and lateral plates, elongated styles curved distally, and a U-shaped aedeagus, with minute teeth ventrally (Figs. 64–68).
In addition to these morphological features, the geographic distribution of Dysyncritus is distinct from other heteronotines. It is presently recorded from Southern Mexico to Honduras, in the northernmost limit of the subfamily’s geographical range. Smiliorachis and Allodrilus gen. nov. are exclusively South American, and the latter are exclusively Amazonian. There are no published life history records for Dysyncritus, except for an observation suggesting that its pronotal color and ornamentation could serve as camouflage (Poulton, 1903a).
description: Published as part of Evangelista, Olivia, Flórez-V, Camilo & Sakakibara, Albino M., 2014, The identity of the treehopper genus Dysyncritus Fowler, with descriptions of new related taxa (Hemiptera: Membracidae: Heteronotinae), pp. 495-532 in Zootaxa 3847 (4) on pages 497-499, DOI: 10.11646/zootaxa.3847.4.2, http://zenodo.org/record/249922