Allotettix simoni (Bolivar, 1890) Pavón-Gozalo & Manzanilla & García-París, 2012

Pavón-Gozalo, Pilar, Manzanilla, Jesús & García-París, Mario, 2012, Taxonomy and morphological characterization of Allotettix simoni (Bolívar, 1890) and implications for the systematics of Metrodorinae (Orthoptera: Tetrigidae), Zoological Journal of the Linnean Society 164 (1), pp. 52-70 : 57-65

REDESCRIPTION OF ALLOTETTIX SIMONI

Adult

Body length: ♂ 9.8–12.3 mm and ♀ 12.0– 13.7 mm. General appearance elongated ( Figs 4A , 5A ). Coloration variable from reddish to olive brown or pale brown ( Fig. 3 ). A pair of white or alternatively dark spots is commonly present in the central part of the pronotum and spots can also be present in the femora. In alcohol, colours became paler and brown predominated. Eyes generally brown, although some individuals present duller coloration.

Head

The head of A. peruvianus is hypognathous, slightly opisthognathous ( Fig. 4A ). Vertex (vx) perpendicular to the medial plane of the body, narrower than the eye or equally wide ( Figs 5A , 6A, C ); in profile, it does not protrude forward between eyes, it forms an obtuse angle with the frontal costa (fc) ( Figs 4A , 6B ); transversal anterior carina of the vertex (tac), straight on its central portion, laterally curved on the sides, originating the lateral carinae of vertex (lcv) along the upper interior edge of eyes ( Fig. 6C ); in frontal view, the transversal anterior carina is depressed twice, at both sides of the frontal costa ( Fig. 6A ). The medial carina (mc) of the vertex extends posteriorly to slightly more than half the length of vertex ( Fig. 6C ). Surface of vertex covered with numerous tuberosities, as well as the frons and genae ( Fig. 6A, C ).

In frontal view, the frons is crossed by the frontal costa (fc) starting at the centre of the transversal anterior carina of vertex (tac) and ending at the level of the median ocellus (mo); a little above the level of the lateral ocelli (lo), the frontal costa bifurcates into two carinae, which remain subparallel and define the longitudinal furrow; the longitudinal furrow extends to the level of the median ocellus ( Fig. 6A ). The carinae are evenly divergent along their length, this is slightly more noticeable below the level of the insertion of the head with the antennae; maximum width of the furrow slightly narrower than width of the first segment of the antennae ( Fig. 6A ); frontal costa subsinuated between the transversal anterior carina and the median ocellus; at the level of the scape of the antennae, in profile, the frontal costa do not protrude forwards of the distal margin of the pedicel of the antennae, and it is elevated, slightly concave, and curved ( Fig. 6B ); below the median ocellus (mo), the frontal carina (fca) bifurcates at two-thirds of its length into two ridges that define the supraclypear triangle (st) ( Fig. 6A ).

Occiput and postgena are not well defined; the external limit corresponds to the occipital suture. The postgenal lobe is practically absent, except for the prolongation of the occipital suture ( Fig. 6B ).

Eyes are globular and prominent both in dorsal and lateral views ( Fig. 6A, B ). In frontal view, lateral ocelli (lo) are located between eyes, at the level of half the length of the eye, at both sides of frontal costa, in contact with the costa. Median ocellus (mo) is placed between the carinae of the frontal costa; ocellus nearly fills the longitudinal furrow; its inferior part is in contact with the frontal carina (fca) ( Fig. 6A ).

Antennae filiform, a little longer than the head, situated between the inferior margins of the eyes ( Figs 6A, C , 7A ). Scape (sc) subtrapezoidal ( Fig. 6B ), followed by a smaller globose pedicel (pd) ( Fig. 7A ) and a flagellum composed of 12 segments ( Fig. 7B ); each of the segments of the flagellum are cylindrical, and three to four times as long as wide; the longest are the central ones; the last one is secondarily subdivided into three. The surface of the antennae is rugose as a result of mound-like protuberances ( Fig. 7C ); other structures with a presumably sensorial function are present in the ventral and lateral surface of the terminal five segments of the flagellum, which include placoid sensillae ( Fig. 7D ), coeloconic sensillae, and some isolated hairs and small tuberosities; density of sensorial structures increasing towards the tip of the flagellum; area with placoid sensillae smooth instead of rugose ( Fig. 7B ).

Clypeus subrectangular, subdivided into anteclypeus and postclypeus; anteclypeus covered by numerous tubers of two different sizes; by contrast, postclypeus smooth and distally membranous; lateral margin of the clypeus subparallel to the frontal costa ( Fig. 6A ). The labrum (lb) is a slightly asymmetrical broad flat lobe, divided into two parts by a transversal furrow; several short furrows cover the central area of the labrum in several directions ( Fig. 6A, B ); the surface of the labrum is completely covered by very small pores.

Mandibles asymmetrical, pyramidal, with a triangular base ( Fig. 8A ); incisor region of the right mandible constituted by five teeth; incisor region (ir) of the left mandible formed by six teeth; teeth sharp and pointed except the basal tooth of the right mandible, which is rounded; basal teeth of each mandible smaller; molar region (mr) oval, with convex surface, crossed by around 20 transversal ridges in parallel disposition, ridges broader in the right mandible; molar region with a tuft of hair and scattered single hairs, which are longer and closer toward the base; surface of the incisor region smooth; surface of the external proximal area of mandibles depressed, containing pores, little tuberosities, and short hairs ( Fig. 8A ).

Cardo (cd) of the maxillae triangular, divided by two perpendicular weak ridges ( Fig. 8B ); the upper part of the external area contains some long simple hairs. Stipes (sp) subrectangular, crossed by a longitudinal ridge, dividing it into an external and an internal area; internal area smaller, concave and rough, as a result of the existence of mound-like protuberances; the longitudinal ridge, together with two other ridges, the transversal and the lateral, define the subrectangular prelacinia; the stipes, closed to the insertion with palpi, presents a deep orifice; surface of the stipes mostly smooth, with some very little pronounced and short ridges, pores, and isolated hairs. Lacinia (la) conical, slightly depressed; apex with four pointed teeth; anterior tooth with the apex distinctly pointed and smaller than the others; external area of the posterior surface of the lacinia with a row of isolated hairs; internal area of the posterior surface of the lacinia shows several parallel rows, although the length of the hairs and the distance between them is shorter than in the external area; the posterior surface of the lacinia contains a pair of pores located in the proximal external corner near a flat oval area. Galea (gl) sickle-shaped, with a rounded tip; its external surface is generally smooth and contains some isolated small pores; internal surface flat, with two rows of hairs in the laterals and some other hairs shorter towards the tip. Palpus (plp) composed of five segments ( Fig. 8B ); first and second segments squat; third, fourth, and fifth segments cylindrical and longer; apex of last segment cupuli- form, very rich in sensilla, rounded by several concentric rows of hairs, similar to the distal apex of the galea; rest of the surface of the palpi with pores and solitary hairs scattered, mostly in the external surface; mound-shape sensilla in the external lateral walls of palpi.

Prementum (pmt), mentum (mt), and submentum (smt) of the labium separated by well-defined subparallel transversal ridges; surface of labium with some isolated pores ( Fig. 8C ). Submentum subtrapezoidal, with posterior angles protruding like a horseshoe; the centre contains two oval smooth areas; lateral margin with some long hairs. Mentum subrectangular, with a small concave area in each side ( Fig. 8C ). Prementum subovate, slightly shorter than the postmentum; anterior margin depressed in the centre; surface smooth, with isolated hairs and pores; troncoconical palpigers ( Fig. 8C ). Palpi (plp) constituted by three segments; first segment as wide as long and second segment about one and a half times the length of the first, both with isolated hairs; third segment longer, claviform; apex of the third segment rich in sensilla, surrounded by several rows of long hairs; mound-shape sensilla in the external lateral walls of palpi. Paraglossae (pg) elongated, rounded, distally convergent, bordering a triangular area where the glossae are included ( Fig. 8C ); its surface presents scattered pores and hairs; apex contains a sensorial area bordered by several rows of hairs. Glossae pointed, conical ( Fig. 8C ).

Thorax

Pronotum (♂ 9.3–11.2 mm and ♀ 11.1–12.4 mm) extending behind the abdomen, reaching the femoral apices or surpassing them ( Figs 4A , 5A ); dorsum somewhat flattened, anteriorly truncate ( Figs 4A , 9A ); apical process tapering and slightly raised at the apex, which is rounded ( Figs 4A , 9C ); humeral angles obtuse; at the level of the humeral angles, pronotum width approximately one-third to one-fifth of its length; in dorsal view, surface of the pronotum granulated and covered by numerous tubercles of different sizes, as previously described for the frons and vertex ( Figs 9A , 10A ).

In lateral view, median carina of the pronotum (mcp) a little elevated, more depressed at the level of anterior half of the anterior carinae, with a little protuberance in the anterior end ( Fig. 9A ). Anterior carinae (acp) slightly convergent and subparallel to the median carina; they are located in an elevated area of the pronotum, whose posterior limit is marked by the anterior transversal furrows (tf) ( Fig. 9A ). In lateral view, there is a second transversal furrow (tf) parallel and posterior to the first; between both anterior and posterior furrows, at the level of the median carina, the pronotum presents a rounded elevation; third transversal furrow and dorsal carinae absent. Inferior carinae weak, parallel to anterior carinae. The humeral carinae (hc) form a right angle with the posterior transversal furrows, and do not reach these furrows. Ventral carinae parallel to lateral carinae, which form acute angles with the humeral carinae.

Ventral carinae, together with humeral carinae, limit the scapular areas; scapular areas have similar ornamentation to the rest of the pronotum, although the distribution is different: there are groups of sensorial structures of small tubercles, whereas other parts are smooth ( Fig. 9B ); several larger tubercles are dispersed, congregated, or even aligned giving the aspect of a carina. In fact, some carinae, such as the anterior carinae, are composed of a succession of aligned tubercles. Numerous unevenly distributed pores are present in the scapular areas. The ornamentation is less dense posteriorly. Margins of the scapular areas straight, subparallel.

In lateral view, the pronotum shows two broad lateral lobes, which form two marked right angles between them and between the superior lobe and the scapular area ( Fig. 10A ); upper lobe asymmetrical with respect to its bisectrix, presenting a shorter upper margin; lower margin of the superior lobe nearly parallel to the median carina; lower lobe larger, subtriangular, nearly symmetrical with respect to its bisectrix and turned downwards ( Fig. 10A ).

Wings and elytra well developed; wings end close to the caudal projection of the pronotum: when closed, wings are covered by the projection; external margin of the wing scalloped; elytra punctuate, oval in lateral view; length of elytra 1.5–2.0 mm, about three times its width.

The pronotum covers all the segments of the thorax in dorsal view. In lateral view, part of the mesothorax and metathorax are visible ( Fig. 4A ) and covered by tubercles similar to those of the pronotum; this area is heavily sclerotized; thus, membranes between segments are indistinguishable. Thoracic spiracles represented by two pairs of small gaps, rounded by sclerotized structures. In ventral view, thorax presents small tubercles and isolated hairs.

Anterior and middle femora compressed; anterior femora less compressed, presenting a single carina in the centre of its external side; middle femora with two parallel carinae along its external side; both upper and lower margins of anterior and middle femora slightly undulate, containing a row of small and pointed spines that give the margins the aspect of carinae; anterior and middle femora are little more than four times as long as wide; their surfaces are covered by multiple tubercles, and close to the inferior margin there are some isolated hairs. Length of hind femora: ♂ 5.0– 5.7 mm and ♀ 5.6–6.7 mm. Hind femora robust, three times as long as wide; upper and lower carinae covered by a row of pointed tubercles; upper and lower internal carinules present tubercles too, although they are less pointed; tubercles are present in all surfaces, as described for head and thorax; pregenicular and genicular teeth rightangular, pointed; genicular lobes round, the upper one dorsally dentate ( Fig. 10B ).

Anterior and middle tibiae distally show a pair of spines in each side of the front face; both anterior and middle tibia sometimes present smaller spines, usually in the distal area. Some hairs present in tibiae. Hind tibiae with the apical third distinctly broader; distally, each tibia exhibits four calcars: two in the rear face, one in the outer face, and one in the inner face; internal apical spine present; there are three to four internal spines in each margin of the rear face; both margins of the rear face dentate as a result of the presence of a row of smaller spines ( Fig. 10C ).

The tarsal formula is 2-2-3 ( Fig. 10C ). First segment of the anterior and middle tarsi four times shorter than the second segment; anterior and middle tarsus with scattered hairs. Hind tarsus consisting of three segments: first and third segments of subequal length; the length of the second segment is half of the length of the first segment; first segment with three pulvilli; first and second pulvilli triangular, pointed and smaller than the third; third pulvilli acute, nearly as long as the first and the second together ( Fig. 10C ). Post-tarsum with two claws. Arolium absent ( Fig. 10D ).

Abdomen

Dorsally, abdomen completely covered by the pronotum; surface with tubercles as for the head and thorax; sternites show isolated hairs in their surface ( Fig. 11A ); abdominal spiracles situated in the middle of the ventral part of each tergum, slightly closer to their anterior limit ( Fig. 11A, B ); spiracles of the first abdominal segment are the largest. Cerci conical and pointed ( Fig. 11C ); anterior half flat, presenting some big pores surrounded by an elevated ring; most of the pores present isolated long setae ( Fig. 11D ), which give cerci the aspect of a tuft ( Fig. 11C ). Posterior half rough, with a similar aspect to the proximal segments of the pedicel of the antennae.

Female: Subgenital plate as long as wide in lateral view ( Fig. 11E ); centre of the posterior margin of the subgenital plate contains a process, the egg-guide, which is small and triangular. Epiproct subtriangular; its centre contains a row of hairs, which are more separated towards its posterior margin; dorsal surface covered by small tubercles. Paraproct also triangular ( Fig. 11F ). Dorsal and ventral ovipositor valves subequal; their apex is hook-like and directed outwards ( Fig. 11E ); both valves present two rows of eight to 12 pointed teeth, which give them a serrated aspect ( Fig. 11F ); length of dorsal valves about three times their width, with teeth along their ventral margins; teeth of ventral valves are placed along their dorsal margins ( Fig. 11E ); number of teeth variable amongst specimens, valves of the same individual and even amongst rows of the same valve; generally, distal teeth of the interior row in the dorsal valves are smaller; each tooth is accompanied by a thick hair ( Fig. 11F ); these hairs appear isolated on the lateral surface of the valves, which also contains several pores.

Male: Subgenital plate elongated, pointed, and subconical upwardly, with the apex truncate ( Fig. 11G, H ). The sclerite of the aedeagus is formed by narrow, thin lateral plates with anterior ends joining to form a small angulate median process covered with denticles. The surface of the pallium is strengthened with two longitudinal sclerotized valves; its outer lateral margins tightly adjoin the margins of the subgenital plate; a pair of longitudinal rods with apical hooks is present between the valves of the pallium.

Last nymphal instar

Body length: 6.2–7.8 mm. Coloration similar to that of the adult ( Fig. 3 ). Head similar to that of the adult ( Figs 4B , 5B , 12A, D ). Flagellum of the antennae composed of 11 segments of variable length ( Fig. 12B ); basal segments short, quadrangular or subrectangular, in some cases as long as wide, or even wider; central and apical segments longer, three or four times as long as their width, or even more; the longest is the seventh, followed by the apical segment, which is subdivided into three ( Fig. 12B ); sensorial area in the last five segments, as in the adult. Transversal furrow of the labrum less noticeable than in the adult ( Fig. 12A ). Molar region of the mandibles less developed than adult, with two or three transversal ridges fewer ( Fig. 12C ). Maxillae more angular; longitudinal ridge of the stipes less marked; internal and external area of stipes similar in aspect; internal area plain and smooth, without mound-like protuberances; prelacinia subtriangular; orifice of the stipes absent. Oval areas of the submentum of the labium are less evident than in the adult.

Pronotum shorter than in the adult (length: 5.4– 6.7 mm), extending behind the abdomen but not reaching the femoral apices; dorsum appearing laterally compressed because of the elevated median carina (Figs 3,4B, 5B, 12D); apex more pointed than in adult and not raised; area where both anterior carinae are located not elevated with respect to the rest of the pronotum. Humeral carinae nearly reaching or in direct contact with the posterior transversal furrows; lateral carinae shorter, extending from the apex of the pronotum to half of the length of the ventral carinae. Scapular areas broader than in the adult; both inferior and superior margins curved outwards, increasing the scapular surface and forming an obtuse angle above and a right angle below. In lateral view, pronotum with a single broad lateral lobe, triangular, turned downwards; lateral margins of the lobe subequal in length; lobe symmetrical with respect to the bisectrix of the angle of the apex; apex of the lobe round; the lobe and the ventral carina leave a gap similar to the lobe in size and shape ( Fig. 12D ).

Elytra not visible. Wings little developed, suboval, covering the lateral surface of the first five abdominal segments; margins of the wings straight, not scalloped; granuli present in all the surface of the wings ( Fig. 12E ).

Anterior and middle femora crossed by two parallel carinae each; these femora nearly four times as long as wide ( Fig. 12F ). Length of hind femora: 4.0– 5.0 mm. Pregenicular teeth of the hind femora absent; antegenicular teeth present, although less prominent than in adult femora.

Differences between the abdomen of the nymph and the adult are marked in the development of genital structures. Posterior half of the cerci elongated, longer than the anterior part, with hyaline aspect ( Fig. 12G ). Female: subgenital plate smaller, slightly less developed; paraprocts smaller than in adult; ventral valves of ovipositor slightly shorter than dorsal valves; apices of valves hook-like, curved and outwards, although less distinctively than adult valves; generally, lower number of teeth in dorsal and ventral valves ( Fig. 12H ). Male genitalia do not present either the sclerotized valves of the aedeago or the pair of longitudinal rods with apical hooks between the valves of the pallium.

Figures

Figure 3. Bayesian phylogenetic hypothesis generated using molecular characters (mitochondrial cytochrome c oxidase subunit I sequence data). Basal branching within Tetrigidae is not supported either by posterior probabilities (Bayesian) or bootstrap values (maximum likelihood). Sequences of Metrodorinae (indicated by pink branches) and Tetriginae (green) do not form reciprocally monophyletic groups. Despite morphological similarity, Allotettix is not a close relative of Paratettix. Nymphs from Aragua (Venezuela) share a single haplotype with adults of Allotettix simoni. Specimens photographed correspond to localities indicated in Table 1.

Figure 4. Dorsal view of: A, adult and B, last nymphal instar of Allotettix simoni from Henri Pittier National Park (Venezuela) (drawing by I. Díez).

Figure 5. Lateral view of: A, an adult female and B, last nymphal instar of Allotettix simoni from Henri Pittier National Park (Venezuela) (drawing by I. Díez).

Figure 6. Environmental scanning electron micrographs of the adult head of Allotettix simoni (Aragua, Venezuela). A, frontal view; B, lateral view; C, dorsal view. Abbreviations: fc, frontal costa; fca, frontal carina; lb, labrum; lcv, lateral carinae of vertex; lo, lateral ocelli; mc, medial carina; mo, medial ocellus; sc, scape of the antennae; st, supraclypear triangle; tac, transversal anterior carinae; vx, vertex. Scale bar = 1 mm.

Figure 7. Details of adult antenna of Allotettix simoni (Aragua, Venezuela), from environmental scanning electron micrographs. A, dorsal view of anterior part of head; B, flagellum of the antennae, note variation on sensorial structures from base to tip; C, mound-like protuberances on antennal surface; D, placoid sensillae on terminal segments of flagellum. Abbreviation: pd, pedicel. Scale bars as indicated in figure.

Figure 8. Environmental scanning electron micrographs of adult mouth parts of Allotettix simoni (Aragua, Venezuela). A, mandibles; B, left maxilla; C, ventral view of labium. Abbreviations: cd, cardo; gl, galea; ir, incisor region of mandible; la, lacinia; mr, molar region of mandible; mt, mentum; pg, paraglossae; plp, palpus; pmt, prementum; smt, submentum; sp, stipes. Scale bars = 500 Mm.

Figure 9. Environmental scanning electron micrographs of thoracic details of Allotettix simoni adult (Aragua, Venezuela). A, dorsal view of anterior portion; B, scapular area; C, lateral view of the terminal portion of pronotum. Abbreviations: acp, anterior carina of the pronotum; hc, humeral carina; mcp, median carina of the pronotum; tf, anterior transversal furrows. Scale bars = 100 Mm.

Figure 10. Thoracic details of Allotettix simoni adult (Aragua, Venezuela), from environmental scanning electron micrographs. See text for detailed description. A, lateral view of anterior portion of body; B, lateral view of hind femur; C, lateral view of the terminal portion of hind tibia and tarsus; D, terminal portion of hind tarsus. Scale bars as indicated in figure.

Figure 11. Environmental scanning electron micrographs of abdominal details of Allotettix simoni adult (Aragua, Venezuela). A, ventral view of terminal portion of abdomen; B, detail of spiracle; C, female cerci; D, detailed view of pores on the female cerci; E, lateral view of female terminalia; F, dorsal view of female paraproct and dorsal ovipositor valves; G, lateral view of male terminalia; H, dorsal view of male subgenital plate and cerci. Scale bars as indicated in figure.

Figure 12. Environmental scanning electron micrographs of last nymphal instar of Allotettix simoni (Aragua, Venezuela). See text for detailed description. A, frontal view of head; B, antenna; C, mandibles; D, lateral view of anterior portion of body; E, wing; F, anterior femur; G, lateral view of nymphal male cerci; H, lateral view of nymphal female terminalia. Scale bars = 500 Mm, except G = 200 Mm.