Gasterocercus hispanicus, Alonso-Zarazaga, Miguel A., Jover, Teresa María & Micó, Estefanía, 2009

Alonso-Zarazaga, Miguel A., Jover, Teresa María & Micó, Estefanía, 2009, A new species of the genus Gasterocercus (Coleoptera, Curculionidae, Cryptorhynchinae) from the Iberian Peninsula, with notes on the ecology of the genus, Zootaxa 2170, pp. 28-36 : 29-34

Gasterocercus hispanicus sp. n.

urn:lsid:zoobank.org:act:445A362A-5A03-4C4D-AAA7-00415902EBA8 (figs. 1–2, 5–14)

Description (holotype). Measurements (in mm): Standard length: 6.32. Rostrum: length: 1.09, maximum width: 0.66. Pronotum: median length: 1.93, maximum width: 2.20. Elytra: median length: 4.39, maximum width: 2.30.

Vestiture composed of scales, each scale discally impressed, slightly striolate; oval, velvety blackish, dark greyish or whitish in colour, the latter forming two vague interrupted elytral fasciae, one pre-median and another on top of declivity, a whitish spot on first interstria and some other scattered, irregular spots; metarostrum with whitish scales, two anterior paramedian pronotal tubercles, scutellum and basal calli of second and third interstria covered with black velvety scales; punctures of elytral striae with one pale brown elongate scale covering most of the puncture; ventral surface mainly whitish, with some sparse dark grey to brownish scales, mainly condensed on disc of fourth and fifth ventrites; antennae without scales, only stiff setae; lateral margins of metarostrum with short semi-erect brownish to whitish scales, forming a conspicuous “beard”; legs with whitish scales, femora with one dark dorsomedian and one genual spot, tibiae with a basal external spot.

Rostrum (fig. 5) in dorsal view 1.65 × longer than wide, widest behind apex, 0.56 × as long as pronotum in midline, mandibles prominent as a quarter of circle, internally not dentate, prorostrum with rounded, moderately deep apical notch, epistome semilunate, smooth, glabrous, impunctate, epistomal keel absent, prorostrum with dorsum sparsely squamose, densely and minutely punctate, the punctures separated by ca. 0.5 × their diameter, appearing rugose and with rounded, denticulate margins, tegument bright between punctures, metarostrum densely squamose, with sides dilated to a tooth-like projection in front of each eye, dorsum with strong median keel extending to median frontal fovea; rostrum in side view straight, flattened, 1.54 × as wide as high.

Head (fig. 5) globular, densely squamose, frons with small median glabrous fovea extended backwards as an obsolete sulcus up to posterior level of eyes. Eyes not more convex than rounded outline of head. Antennae inserted at basal 0.49 of rostral length, with scape strongly clavate from basal third, 2.7 × longer than wide, as long as first 4 desmomeres together, slightly compressed. Pedicel as long as desmomeres 2+3, 1.83 × long than wide, 2nd desmomere 1.3 × longer than wide, 3rd to 5th slightly transverse, 6th and 7th isodiametric, 7th a little larger than 6th. Club oval, 2.0 × longer than wide, as long as last 5 desmomeres together, densely sericeous.

Pronotum campanulate, transverse (0.87 × as long as wide), widest a little behind middle, strongly constricted in anterior third, apex slightly emarginate between the two apical tubercles, hind angles subrotundate, base 1.45 × wider than apex, disc almost flat, in side view dorsal line slightly convex. Scutellum slightly transverse (0.91 × as long as wide), subpentagonal, densely punctate.

Elytra 1.91 × longer than wide, sides subparallel to apical third, jointly rounded at apex, humeral calli slightly prominent, with 9 complete striae, 10th short, joining 9th at metacoxal level; striae with oblong large punctures separated by a distance of about their length; interstriae moderately convex on disc, 1st and 3rd narrower than remainder, 2nd and 3rd united at base in a strong oblique callus, shifted outwards and prominent over elytral base outline, 3rd and 9th at apex costiform and united, 5th prominent before umbo.

Prosternal channel deep, wide, procoxae separated by a little more than their transverse diameter, apically acutely dentate. Mesosternal receptacle with posterior wall very prominent, externally with strong median keel, strongly depressed on each side of the latter, fore margin roundly emarginate. Mesocoxae separated by a distance slightly shorter than their width. Metasternum 1.3 × longer than length of mesocoxa, with a median sulcus in posterior half and a semilunate depression bordering the postero-internal margin of each mesocoxa. Sclerolepidia absent.

Abdomen with 1st ventrite behind metacoxae as long as 2nd, this shorter than 3rd + 4th, suture I procurved at middle, deep at sides, shallow at middle, suture II postcurved, 5th strongly transverse, convex, apex truncate. Intermetacoxal apophysis subogival, laterally angulose, with an anterior transverse depression. Seventh tergite (propygidium) densely punctate, with large folding patches and a smooth median sulcus, two prominent plectra (type I of Lyal & King (1996)) and fore margin prominent at middle (fig. 8). Eighth tergite (pygidium) more or less semicircular (1.59 × wider than long), slightly truncate apically, with a blunt median longitudinal keel covered with scales, in ventral view with small spiracles (fig. 13), which are probably nonfunctional. Ninth sternite (spiculum gastrale) asymmetrical, with long, slightly curved apophysis (fig. 10).

Profemora moderately robust, with a blunt denticle. Tibiae almost straight, uncus strong, praemucro small, covered by scales. First tarsomere longer than wide, 2nd slightly longer than wide, subquadrate, 3rd subcordiform, transverse, onychium projecting from lobes of 3rd by 2 × its apical width. Mesofemora shorter, with no visible denticle, metafemora more elongate, without denticle. Trochanteral setae absent. First protarsomere with a fringe of short, dark setae on inner margin, also some on base of 2nd, these much shorter than width of tarsomere.

FIGURES 7–8. Gasterocercus hispanicus sp. n., 7th tergite. 7. female paratype, scale: 1.67 mm; 8. holotype male, scale: 0.78 mm.

Genitalia: Aedeagus in dorsal view (fig. 11) with sides subparallel, slightly dilated at ostium level, apical plate subtriangular with sides rectilinear, narrowly rounded at apex; in side view (fig. 12) slightly curved, robust, apex straight, rather narrow. Tegmen widely Y-shaped, dorsal part of ring membranous.

Variation. Male paratypes. Measurements (in mm, n = 8): Standard length: 6.62–9.48. Rostrum: length: 1.32–2.15, maximum width: 0.75–1.10. Pronotum: median length: 2.15–3.22, maximum width: 2.37–3.57. Elytra: median length: 4.47–6.26, maximum width: 2.57–3.83. Ratios: rostrum length/width: 1.76–1.95; pronotum length/width: 0.90–0.92; elytral length/width: 1.63–1.74; rostral length/pronotal length: 0.61–0.67. These measurements show the holotype to be the smallest specimen of the type series. Larger males tend to have longer front legs, with a longer protarsal fringe, which may be slightly longer than the width of the first tarsomere, and the sides of the pronotum more angulate.

Female paratypes. Measurements (in mm, n = 6): Standard length: 6.59–9.11. Rostrum: length: 1.32–1.89, maximum width: 0.61–0.81. Pronotum: median length: 1.98–2.70, maximum width: 2.15–3.13. Elytra: median length: 4.61–6.41, maximum width: 2.52–3.60. Females differ from males by the rostrum in dorsal view (fig. 6) being 2.16–2.69 × longer than wide, 0.66–0.71 × as long as pronotum, prorostrum minutely punctate, on dorsum punctures separated by 1.0–1.5 × their diameter, more confluent and denser on sides and apical angles, tegument between punctures brighter and smoother, with a median impunctate line posteriorly confluent with metarostral median keel; apical notch wider, less deep. The metarostral lateral semierect scales are absent, the metarostral lateral teeth blunter, the antenna inserted at the basal 0.43 of the rostral length, the pronotum 0.86–0.93 × as long as wide, widest before base, the elytra 1.77–1.83 × longer than wide, slightly widest in apical third, subparallel, the 5th abdominal ventrite strongly transverse, rather flat, with a subtruncate, more rounded apex, the 7th tergite (pygidium) 1.10–1.20 × wider than long, trapezoidal, projecting at midbase, and the plectra smaller than in male but otherwise similar, with rounded, subtruncate apex (fig. 7). Genitalia (fig. 9): 8th tergite slightly sinuate at apex, subtrapezoidal, with a longitudinal sclerotised reinforcement on each side; 8th sternite with a subrectangular plate, apex slightly widened and setose, anterior angles well marked, almost right, plate slightly shorter than apophysis; ovipositor lightly sclerotised, ca. 3.5 × longer than wide, undivided, styli ca. 2.5 × longer than wide, setose; bursa copulatrix with no visible hard structures; spermatheca C-shaped, body subglobose, cornu short.

FIGURE 10. Gasterocercus hispanicus n.sp., terminalia, holotype male. 10. spiculum gastrale, scale: 0.1 mm; 11. aedeagus, dorsal view, scale: 0.1 mm; 12. aedeagus, lateral view, scale: 0.1 mm; 13. 8th tergite, ventral view, scale: 0.2 mm.

Material examined. Holotype male, head and pronotum mounted separately from hind body and elytra, labelled: (white, printed): Valle de Viñuelas, P.N. Cabañeros, CIUDAD REAL, 12-VI-2005 / 5-VII-2005, T. Jover leg. / (white, handwritten): 2263 / (white, printed): ɗ; genitalia and abdominal pieces mounted in two separate cards below (in Col. Alonso-Zarazaga, MNCN, Madrid). Paratypes: 1 Ψ, same data as holotype except for Ψ symbol (in entomological collection of University of Alicante, CEUA); 2 Ψ: Hispania, Fuencaliente (CR), Sierra Madrona 14-VII-2005 – RCA2, Lencina & Andújar leg. / Gasterocercus / depressirostris / (Fabricius, 1792) / det. J. L. Lencina 2007; 1 ɗ: Hispania S. de San Vicente, Almendral de la Cañada (TO) 18.VI.2005 luz, Lencina & Andújar leg. / same identification label; 3 ɗ, 2 Ψ: Fuencaliente (CR), Sierra Madrona, Robledal de las Hoyas, TIV RHR1 29-VI-2005, J.L. Lencina & C. Andújar leg. (one female in very poor state); 1 ɗ, 1 Ψ: Fuencaliente (CR), Sierra Madrona, Río Cereceda, robledal, 14-VII-2005, J.L. Lencina & C. Andújar leg.; 1 ɗ: Fuencaliente (CR), Sierra Madrona, Río Cereceda, aliseda-robledal, 14-VII- 2005, J.L. Lencina & C. Andújar leg. (in poor state); 2 ɗ: Hinojosa de San Vicente (TO), Sierra de San Vicente, robledal del Piélago, 4-VII-2005, J.L. Lencina & C. Andújar leg. (the last 13 paratypes to be deposited in Col. Alonso-Zarazaga, MNCN, Madrid (4), Col. Andújar (2), Col. Zoological Department, University of Murcia, DZUMU (2), Col. Lencina, Museo de Ciencias Naturales, Jumilla (5)).

Etymology. The specific epithet is a Latin adjective referring to Spain.

Diagnosis. This new species differs from the Palaearctic G. depressirostris by the characters listed in Table 1 .

Distribution and habitat. This species is distributed in the mountainous areas of the provinces of Toledo and Ciudad Real in central Spain (fig. 14). From the 49 window traps monitoring four different types of forest ( Quercus suber , Q. pyrenaica , Q. faginea and Fraxinus angustifolia ) used in the Cabañeros N. P., the specimens of Gasterocercus hispanicus were collected in a single trap in the Q. pyrenaica oak forest, situated in the sampling plot of the site known as “Valle de Viñuelas”. The trap was placed on a Q. pyrenaica tree of 1.43 m base diameter. The site was characterised by a shrub stratum with moderate coverage (<15%) formed by six species, dominated by Erica arborea , and a herbaceous stratum formed by 23 species and with a dense coverage. The forest is estimated to be 80–120 years old [estimation performed using a Presler drill and data extrapolated using the diameter of trees inside the park ( Diéguez et al. 2003; Rozas 2004)] and presented a high amount of dead wood on the ground (2m 3) [the volume of dead wood measured in plots of 40 m 2] constituting the most mature forest mass from the five areas in the park studied. From the other six localities, ten specimens were collected in Q. pyrenaica forest, two in mixed Quercus forests and one in mixed Quercus - Alnus forest.

Biology. Adults have been collected in summer (from 12–VI–2005 to 14–VII–2005). The qualitative analysis of gut contents showed recognisable fungus spores.

Tables

TABLE 1: Diagnostic characters of G. hispanicus sp. n. and G. depressirostris.

Character	G. hispanicus sp. n.	G. depressirostris
Colour pattern	black-grey-whitish (figs. 1–2)	dark brown-castaneous-cream (figs. 3–4)
7th desmomere	isodiametric (fig. 5)	transverse (0.8 × as long as wide)
Fringe of 1st protarsomere of male	at most barely longer than wide, black	much longer than wide, yellowish to light brown
Posterior wall of receptaculum	more prominent and steeper	less prominent, very oblique
1st abdominal ventrite behind metacoxae	as long as 2nd	1.2 × as long as 2nd
Abdominal suture I	shallow at middle	as deep medially as laterally
Apical plate of aedeagus in dorsal view	subtriangular with sides rectilinear, narrowly rounded at apex (fig. 11)	semicircular with sides evenly rounded
Apex of aedeagus, lateral view	straight, rather narrow (fig. 12)	deflexed, more robust