Systellonotus stysi, Ribes & Pagola-Carte & Heiss, 2008

Ribes, Jordi, Pagola-Carte, Santiago & Heiss, Ernst, 2008, Two new Phylinae (Hemiptera: Heteroptera: Miridae) from the Canary Islands, Acta Entomologica Musei Nationalis Pragae 48 (2), pp. 423-431 : 424-427

Systellonotus stysi sp. nov.

( Figs. 1-3 )

Type locality. Canary Islands, Tenerife, Los Cristianos.

Type material. HOLOTYPE: ♀, ‘TENERIFE / Los Cristianos / 7- II-57 J. de Ferrer’ [white, handwritten label] // ‘ HOLO- TYPE / Systellonotus stysi n. sp. / J. Ribes, Pagola-Carte / & Heiss, 2008’ [red, typewritten label] . PARATYPES: 1 ♀, ‘ Isl. Can. , Tenerife / Adeje, Bco. del In- / fierno, 400m, / Euphorbia carariensis [sic!] / 9.IV.1992,leg. Zerche’ [white, typewritten label] ; 1 ♀, ‘La Palma / Volcán Martín / VIII-86 / P. Oromí’ [white, handwritten label]. Both paratypes: ‘ PARATYPE / Systellonotus stysi n. sp. / J. Ribes, Pagola-Carte / & Heiss, 2008’ [red, typewritten label].

Holotype and paratypes mounted on a card; the female paratype from La Palma with the genitalia glued on a second card below. Holotype deposited in the collection of J. Ribes (Barcelona, Spain); paratypes deposited in the collections of E. Heiss ( Innsbruck , Austria) and Pagola-Zabalegui (Donostia, Spain), respectively .

Description. Length: 3.50-3.85 mm.

Body surface shiny. Dorsal colouration reddish brown or golden brown, with abdomen darker brown ( Fig. 1a ). Dorsal vestiture of head, pronotum, scutellum and hemelytra consisting of erect, pale setae, shorter than or as long as the diameter of anterior tibiae. Dorsal vestiture of abdomen consisting of semierect, stout, pale uniformly scattered hairs, twice as long as the diameter of anterior tibiae.

Head in dorsal view ( Fig. 1b ) almost spherical, 1.2 times as long and 1.6 times as wide as pronotum. Eyes relatively small and flattened, postocular region rounded and strongly constricted towards pronotal collar. Head in frontal view ( Fig. 2b ) subtriangular and approximately as high as wide; antennal fossae equally distant from the inferior margin of eye and the base of clypeus. Head in lateral view ( Fig. 2a ) ovoid, gula slightly curved and covered by erect hairs like the juga; clypeus weakly protruding and separated from frons by a slight transversal sulcus; maxillary plates small.

Rostrum reaching or slightly surpassing metacoxae, reddish brown in colour. Segment I thick and nearly as wide as segment I of antennae, its basal half concealed by small bucculae, the latter antero-laterally projected and visible in frontal view ( Fig. 2b ); segments II, III and IV thinner.

Antennae stout; segment I thick, cylindrical, pale brown; segment II brownish with darker apex, slightly to distinctly arched in its basal half and somewhat enlarged apically ( Fig. 2a ); segment III cylindrical, its basal half whitish and apex blackish; segment IV fusiform, black ( Fig. 1a ). Length of antennal segments I-II-III-IV = 0.30-1.05-0.65- 0.50 mm. Ratio of segments III/II = 0.62.

Ocular index = 4.32-4.65.

Pronotum 1.18 times as long as wide and 1.4-1.5 times as long as scutellum, dorsally globose with rounded lateral margins ( Fig. 1b ); collar ( Fig. 2a ) depressed, flattened and finely granulate; posterior margin emarginate and depressed, finely granulate. Supracoxal lobes of fore legs visible from above on the sides of pronotum.

Scutellum triangular, nearly as wide as long, lateral margins slightly convex. Disc with a distinctive conical hump on posterior half, its apex blunt, as high as the upper level of head and pronotum ( Figs. 2a,c ).

Hemelytra without membrane, shiny, distinctly surpassing the apex of scutellum ( Fig. 1b ), subparallel at base and then convex, posterior part of triangular shape and strongly turned upward ( Figs. 2a,c ). Clavus indistinct, claval suture short (0.35 times as long as scutellum) but distinct. Exocorium with a longitudinal whitish spot, not reaching anterior and posterior apices of corium ( Fig. 1b ).

Abdomen transversally arched or swollen in semicircle; colouration brown with darker terminal segments; connexivum reflexed dorsally ( Fig. 1a ).

Evaporatory area of metathoracic scent glands very prominent, transverse, of ivory-whitish colour ( Fig. 2c ), with a robust peritreme and a large orifice bordering metacoxae.

Legs long and slender. Tibiae with short, reclining, brown hairs and short, isolated spines arranged along the inner sides. Length of metatarsus = 0.43 mm; claw of metatarsus = 0.08 mm; length of metatarsal segments I-II-III = 0.17-0.23- 0.17 mm ( Fig. 2d ).

Female genitalia. Dorsal wall of gynatrial complex as in Fig. 3 . See remarks in the Discussion.

Male unknown.

Etymology. We are pleased to dedicate this species to our friend Pavel Štys on the occasion of his 75 th birthday as a recognition of his many and great contributions to our knowledge of the Heteroptera .

Distribution. So far only known from two of the Canary Islands: Tenerife and La Palma.

Discussion. Systellonotus stysi sp. nov. shares the set of diagnostic characters of the mainly Mediterranean genus Systellonotus (see WAGNER 1974), except the ratio of segment III to segment II of antennae, which is only 0.62 in contrast to the minimum value of 0.75 given by WAGNER (1974). In our view, this is a variable character and we suggest extending the range of the ratio down to 0.60. In his key, WAGNER (1974) stated: ‘Selten ist das 3. Glied kürzer als das 2., dann sind die Augen vom Vorderrande des Pronotum entfernt’ [= Rarely is segment III shorter than II, but then the eyes are distant from the anterior pronotal margin]. However, the ratio is smaller than 1 in most species of Systellonotus (mostly in the range of 0.8-0.9). Systellonotus stysi sp. nov. shares both characters as the antennal segment III is shorter than segment II and the eyes quite distant from pronotal collar.

Within the Systellonotus group of genera sensu SCHUH (1974) and LINNAVUORI (1996), Systellonotus is included in the first subgroup of genera ( LINNAVUORI 1996), which displays a striking tendency towards an ant-like appearance. The myrmecomorphic features include the development of a scutellar hump, observed in a few genera, which resembles a hump on the basal abdominal tergite of some ants.

Due to the possession of such a hump and some other morphological adaptations (small eyes, general habitus, etc.), S. stysi sp. nov. could be misplaced, at first glance, in the mainly African, ant-mimetic genus Aspidacanthus Reuter, 1901 . Nevertheless, it clearly lacks a number of generic diagnostic features of the latter genus (according to LINNAVUORI (1996): antennal fossae closer to eyes, neck narrower, rostrum shorter, posterior part of pronotum strongly widened, claval suture not developed, tarsal segment III longer than II). In fact, various myrmecomorphic characters have evolved separately in different lineages. For instance, the genus Laemocoris Reuter, 1879 , which also includes both African and European species, belongs to the Hallodapus group of genera ( LINNAVUORI 1996) but shows a strongly ant-mimetic appearance as well, and most of its species possess a scutellar hump.

MAGNIEN (2000), in his revision of the genus Cremnocephalus Fieber, 1860 , was the first to deal with the female genitalia in the tribe Hallodapini . More recently, WYNIGER (2006) examined and illustrated the dorsal and posterior walls, the ventral sac and the vestibulum of 10 species belonging to five genera in a comprehensive study of Central European Hallodapini . Concerning the dorsal view of the gynatrial complex, she has shown that the three species of Systellonotus studied ( S. alpinus Frey-Gessner, 1871 , S. discoidalis Horváth, 1894 , and S. triguttatus (Linnaeus, 1767)) are diverse in the shape of their sclerotized rings (more or less circular or triangular, pointed or rounded apically, and with or without an auricle-like apex) but always have voluminous lateral oviducts. In S. stysi sp. nov., those structures ( Fig. 3 ) are more similar to WYNIGER’ s (2006) drawing for Omphalonotus quadriguttatus (Kirschbaum, 1856) due to the more roundish sclerotized rings, less voluminous lateral oviducts, general shape of the gynatrial complex and membranous, U-shaped antero-medial fold.

Despite these similarities in the female genitalia, S. stysi sp. nov. cannot be included in the genus Omphalonotus Reuter, 1876 , because of the quite different external morphology. In Omphalonotus , the eyes are in contact with the anterior margin of the pronotum, the ratio of segments III and II of the antennae is close to 1, and the body shape is rather different. However, one morphological feature of the new species deserves attention, since it is shared with Omphalonotus : the prominent bucculae, which are similar to those of O. quadriguttatus as illustrated by WAGNER (1974: p. 325: Figs. 571c-d), but different to those previously outlined by WAGNER & WEBER (1964: p. 369: Figs. 205c-d). Although the prominent structures are referred to as the maxillary plates (= ‘brides’ in French; ‘Zügel’ in German) in both books ( WAGNER & WEBER 1964, WAGNER 1974), they actually represent bucculae in the more recent book as well as in our specimens of S. stysi sp. nov. ( Fig. 2b ).

Figures

Fig. 1. Systellonotus stysi sp. nov., paratype ♀ from Tenerife. a – habitus, b – head and thorax.

Fig. 2. Systellonotus stysi sp. nov. a – head and anterior portion of thorax in lateral view (vestiture omitted); b – head in frontal view (vestiture and antennae omitted); c – anterior half of body in lateral view; d – tarsus of middle leg.

Fig. 3. Female genitalia of Systellonotus stysi sp. nov.: dorsal wall of gynatrial complex. Scale bar = 0.2 mm.