Elsiella plana ( Walker, 1867 )

Simões, Felipe Lorenz, Ferrari, Augusto & Grazia, Jocélia, 2012, Is Elsiella Froeschner, 1981 a valid genus? (Hemiptera: Heteroptera: Pentatomidae: Pentatominae), Zootaxa 3238, pp. 39-48 : 41-44

Elsiella plana ( Walker, 1867)

Ebora plana Walker, 1867: 416 –417.

Elsiella plana ; Froeschner, 1981: 532 –536.

Description ( Figure 1 . A–B). Oval body, flat dorsal surface, with a slight depression in scutellum, and ventral surface convex. Body light brown, with dorsally dense and ventrally sparse black punctures.

Head ( Figure 1 . C) triangular, 1,25x longer than wide; lateral jugal margins sinuous, slightly arched, surpassing clypeus, thus forming a “V anteriorly; punctures on jugal apices slightly punctured. Eyes concolorous. Ocelli reddish. Rostrum reaching at least 3rd coxae; rostrum segments: IV<III<I<II; II segment smaller than III+IV. Buccula margins sinuous, parallel, elevated anteriorly, decreasing in height, evanescent posteriorly, and not reaching base of head. Antennal segments: II<I<III<IV<V, segment V whitish on its basal 3/4, apex black. Pronotum trapezoidal, 2x wider than long; anterolateral angles with small pointed denticle directed laterad; anterolateral margins straight, outlined in yellowish brown; humeral angles not developed, slightly obtuse; posterolateral margins almost straight; posterior margin straight; cicatrices concolorous with dorsal surface of body, except with median dense dark punctures.

Scutellum triangular with a slight median depression, basally longer than wide; lateral margins sinuous; each basal angle with small dark fovea; apex slightly acute. Hemelytra. Corium longer than scutellum, apices reaching to middle of connexivum VI segment; evenly punctured; dark brown membrane, with five main veins these invisible at base ( Figure 1 . D).

Legs immaculate, paler than body; tibiae slightly sulcate. Connexivum exposed, immaculate, yellowish brown, posterolateral angles slightly produced. Mesosternum linear, carinate; metasternum hexagonal surrounded by slightly elevated carina; ostiole with small peritreme, metapleural evaporatorium reaching 1/4 of the width between ostiole and metapleural lateral margin. Abdomen not medially sulcate; spiracles round, black, placed anteriorly to transverse suture of segments; trichobothria placed laterad of spiracles and behind transverse suture of segments.

Measurements. Length, male and female: 11.5; other morphometric parameters in Table 1 .

Female genitalia ( Figure 1 . F; Figure 2 . D). Genital plates coarsely punctured. Gonocoxites 8 (Gc8) quadrangular with a slight central depression, longer than laterotergites 9 (La9), posterior margins straight; sutural margins straight and juxtaposed in its whole length; sutural angles almost rectilinear and not produced. Laterotergites 8 (La8) with spiracles, equal in length to La9; posterior margin almost straight with a small projection (in the holotype, the La8 are more obtuse). La9 convex in most of its surface, surpassing dorsal band uniting La8. Segment X rectangular, lateral margins obscured by La9. Gonocoxites 9 (Gc9) diamond-shaped, surface slightly convex, lateral margins slightly projected towards La9.

Male genitalia ( Figure 1 . E; Figure 2 . A–C). Pygophore posterolateral angles produced. Inferior ridge of ventral rim with 1+1 median spatular projections, obtuse at apex; membranous area between superior and inferior ridges strongly bristled. Pygophoral dorsal rim in shallow U-shaped excavation. Segment X quadrangular, transversally placed to body's longitudinal axis, basal fourth limited by a transverse carina. Parameres hook-shaped, head acuminate towards apex and directed to the carina of segment X.

Type-material. Female holotype with the following labels: a) Archidona 53 12, b) Probably Holotype of Ebora plana Walker, 1867:416 . Det. W. R. Dolling 1979 [ ECUADOR. Província de Napo, 0º 55' 0S / 77º 47' 60"W], deposited at Natural History Museum, London, United Kingdom. Examined.

Material examined. ECUADOR. Província de Napo: Baeza , 2000 m, 0º 27' 0" S / 77º 52' 60" W, 1 female, 1– 9.III.1979 M. Kaulbars ( NDSU); compared to holotype of E. plana . COLOMBIA. Departamento de Cauca: Cauca, 2º 34' 16" N / 76º 46' 45" W, 1 male, Phereclus pluto affinis Stål, Naturhistoriska Riksmuseet Stockholm Loan no. 489/99 ( NHRS).

Cladistic analysis. Seven most parsimonious trees (Length=86; CI=50; RI=75) resulted from the data set analysis. The strict consensus tree ( Figure 4 ) has 93 steps, a consistency index of 46, and a retention index of 70.

The relationship found in the previous analysis ( Fortes & Grazia, 2005) between Serdia and Similliserdia is still supported by characters 2, 5, 11, 22 and 26 despite the change in status of characters 11 and 22 (peritreme and superior ridge of ventral rim of pygophore, respectively), previously considered as synapomorphies and now interpreted as homoplasies because they occur in Elsiella plana . The other relationships were also unaltered and the remaining character distribution was maintained.

E. plana is placed close to the root and outside the other groups: Tibilis, Neotibilis, Similliserdia , and Serdia. As Tibilis is the root, the relationship between Elsiella and Tibilis is not confirmed. The intimate relationship between Elsiella and Serdia, suggested by Froeschner (1981), was not corroborated.

The differences pointed out by Froeschner (1981) to distinguish Elsiella from Serdia, were the length of the antennal segment II, the metapleural evaporatorium texture, and the general color of the body and punctuation. The addition of the distinct morphology of the male genitalia of E. plana , and present cladistic analysis, supports considering Elsiella as a valid genus, despite the lack of data regarding the internal genitalia characters. Among the characters, it is possible to highlight the ventral rim projections of the inferior ridge of E. plana pygophore, which are unique.

Otherwise, the data available did not allow inferring Elsiella ’s phylogenetic position in relation to the other genera studied, which thus supports the decision to keep Elsiella as a monotypic genus. On the monophyly of monotypic genera, Platnick (1976) said “there seem to be two cases (when the genus is monotypic), one in which the sister taxon or taxa of a given species are known and one in which they are unknown”. The latter seems to be the case for Elsiella: it is established without synapomorphies grouping it with other genera ( Wiley, 1977 and Platnick, 1977).

Figures

FIGURE 1. Elsiella plana: A. Female dorsal facies; B. Male dorsal facies; C. Head; D. Hemelytron; E. Pygophore, dorsal view; F. Female external genitalia, posteroventral view (bar = 1 mm).

FIGURE 2. Male and female genitalia of Elsiella plana: A, pygophore, dorsal view; B, pygophore, ventral view; C, pygophore, posterior view; D, female external genitalia posteroventral view (dr = dorsal rim; sp = spiracles; vr = ventral rim; pir = 1 + 1 projections of inferior ridge of ventral rim; par = parameres; Gc 8 = gonocoxites 8; Gc 9 = gonocoxites 9; La 8 = laterotergites 8; La 9 = laterotergites 9; X = tenth segment) (bar = 1 mm).

FIGURE 4. Strict consensus tree of seven trees (length = 93 steps; CI = 46; RI = 70). Analysis under equal weights. Bremer supports are shown below the nodes. Only unambiguous changes are shown.

Tables

TABLE 1. Morphometrical parameters of Elsiella plana (measurements in millimeters).

		E. plana 3	E. plana Ƥ
Head length		2	2.72
Head width		2.56	2.8
Interocular distance		1.84	1.92
Antennal segments length	I	0.74	1.01
	II	0.81	0.78
	III	1.01	1.28
	IV	-	1.83
	V	-	2.34
Rostral segments length	I	0.94	1.01
	II	1.09	1.33
	III	1.33	1.52
	IV	1.05	1.21
Length in front of eyes		1.2	1.68
Pronotum length		2.88	3
Pronotum width		6.56	7.12
Scutellum length		4.72	5.04
Scutellum width		3.84	4.56
Abdominal width		7.2	7.76
Corium length		6.88	8