Pacholenus monteiroi, Vanin, 2008

Vanin, Sergio Antonio, 2008, A new species of PACHOLENUS Schoenherr from southeastern Brazil (Coleoptera, Curculionidae, Molytinae), and new occurrences of species of the genus, Papéis Avulsos de Zoologia 48 (30), pp. 345-351 : 347-350

Pacholenus monteiroi sp. nov.

( Figs. 1-7 )

Type-material: Male holotype “Carapebus, RJ, Parque Nacional da Restinga de Jurubatiba, 03.VIII.2006, Ricardo F. Monteiro col.; Espécie indutora de galha” ( MZSP), dissected. Paratypes, same data, (2 males, 2 females, MZSP); same data but 06. IV .2006 (1 male, 1 female, MZSP); “Est. São Paulo, Guarujá, I. XI.1920, Mehu; Pacholenus sp. , S.A. Vanin det. 1992” (1 female, MZSP) .

Diagnosis

Integument reddish brown covered by whitish decumbent and erect scales, denser especially on sides of pronotum and on elytral disc. Each supra-ocular ridge with a brush of large and erect dark orange scales. Elytra more or less parallelsided, only narrowed near jointly rounded elytral apices; elytral declivity very abrupt, with a sinuous transverse band of spatulate and erect white scales.

DESCRIPTION

Length (in mm, rostrum excluded): male 4.2-5.0; female 5.5-6.4.

Head: Rostrum shorter than pronotum (males and females), in males about 0.85 times and in females 0.75 times as long as pronotum; in males more strongly arched from near antennal insertion to apex; base wider at apex than at base (1.2 times) in both sexes; scrobes deep, on ventral face of rostrum obliquely directed to base but not meeting each other. Antennae near apical third of rostrum; apex of scape extended to anterior margin of eye; flagellomere I wider and longer than any of the following flagellomeres, about 1.4 times as long as II; III-V subequal, about as wide as long; VI and VII slightly wider than long; club fusiform, sutures inconspicuous, about 2.2 times as long as wide, and nearly as long as the flagellomeres II-VII combined. Eyes oval, narrowed ventrally, dorsally separated by slightly less than rostrum width at base; ommatidia coarse, with 9 to 10 facets at widest point and about 22 on length; dorsal outer margin of eyes fringed with oval orangish scales. Frons with a pair of supra-ocular ridges, more prominent in males, each one with a brush of hirsute, spatulate dark orange scales; with an elongate feeble depression between eyes. Rostrum and remaining parts of dorsum of head with elongate dark orange scales, ventrally glabrous.

Pronotum about as long as wide, widest about middle, with lateral sides gently curved towards apex and base; front margin produced into a bilobed medi- an projection, protruded above head; postocular lobes rounded, well indicated; vibrissae well developed. Surface with coarse and more or less sparse foveolate punctures, which are masked by the cover of white decumbent scales; vestiture longer and denser at lateral sides; region of bilobed projection with dark orange and dark brown elongate scales.

Scutellum rounded, covered by white scales.

Elytra slightly wider than pronotum, 2.6-2.7 times as long as wide, more or less parallel-sided, only narrowed near jointly rounded apices; elytral declivity very abrupt near apex, declivous region of each elytron deeply concave. Striae very coarse, formed by foveolate punctures, about as large as interstriae width. Surface covered by small, white decumbent scales; with some sparse blak elongate scales on sutural interstriae. Interstriae I (= sutural interval) slightly raised near base and more strongly raised on elytral declivity; interstriae III weakly raised near base; dorsal surface of elytra with a sinuous transverse band of white scales, beginning in elytral suture and reaching striae IX; with, erect, dark brown spatulate scales in front of white transverse band, forming clusters on raised elytral suture and on prominent tuberosity formed by confluence of interstriae III-V.

Front femora bearing four long stiffed setae; each femur with one large triangular tooth, inner margin straight, outer margin sinuous, and with one smaller tooth, very acuminate, placed between the larger one and the apex of femur; tibiae short and strongly curved. Legs with white and setiform scales. Ventrites I and II, and III and IV, with about the same length, but II about 1.4 times as long as III and IV combined; sutures between ventrites I and II obliterated; ventrite II with distal margin regularly curved from base, slightly shorter than III and IV combined.

Male genitalia: Median lobe of aedeagus 4 times as long as wide, basal apodeme very slightly shorter than median lobe; apex very acuminate; internal sac (= endophallus) with a small, foliaceous and concave sclerite, surrounded by microtrichiae. Apodemes of tegmen about 0.7 times as long as apodemes of aedeagus.

Ventral integument darker than integument of dorsum and of legs.

Etymology: It is a pleasure to name the new species in honor of Dr. Ricardo F. Monteiro, in recognition of his significant contributions to the knowledge of the biology of weevils.

Geographic distribution: Southeastern Brazil, from Rio de Janeiro south to São Paulo, along the coast .

Type locality: BRAZIL, Rio de Janeiro state, Carapebus, Parque Nacional da Restinga de Jurubatiba .

Host relationships: Pacholenus monteiroi develops as a stem gall-former in Calyptranthes brasiliensis Spreng (Myrtaceae) .

Remarks

Pacholenus monteiroi is best characterized by the prominent supra-ocular ridges, each one with a brush of large and erect dark orange scales ( Figs. 3 and 4 ), unique in the whole genus. In the other known species of Pacholenus , the frons close to the upper margin of eyes are not elevated, but has a similar brush of erect, spatulate, orange scales.

Males are distinguished from females by the beak being slightly shorter, more abruptly curved near antennal insertion, and more rugose and more scaled than that of female. Furthermore, the supra-ocular ridges and the brushes are more developed in males.

Pacholenus monteiroi should be confused with P. canescens , both species sharing the elytral interstriae III weakly raised near base and the whitish dorsal vestiture. However, in P. canescens the elytral declivity is not abrupt, without tumescence or special vestiture, while in P. monteiroi the elytral declivity is very abrupt, with tumescences on sutural area and in the confluences of interstriae II-V, and has a transverse band of white scales. The new species is, up to now, the smallest member of the genus (4.2-6.4 mm); another small species is P. hispidus , but it is slightly larger (6.7-8.5 mm) and well characterized by the strong scaly tumidity of suture on elytral declivity.

The known host of P. monteiroi is Calyptranthes brasiliensis Spreng , and those of P. pelliceus are Gomidesia martiniana Berg and G. fenzliana Berg ( Vanin et al. 2000) . Thus, these two species of the genus Pacholenus develops as stem-galls of plants of the family Myrtaceae . According to Souza et al. (2007), Calyptranthes brasiliensis Spreng is a brush or a tree which may reach eight meters high, ranges from Bahia south to Santa Catarina, and may inhabit the Tropical Rain Forest, the Restinga vegetation and the “Mata de Tabuleiro” of Espírito Santo state. Details concerning the gall structures and the weevil biology will be published elsewhere by Dr. Monteiro and collaborators.

Figures

FIGURE 3: Pacholenus monteiroi sp. nov., female paratype from Carapebus, RJ; detail of head, pronotum, and right anterior leg, dorsal view.

FIGURES 1-2: Pacholenus monteiroi sp. nov., female paratype from Carapebus, RJ, habitus; 1, dorsal view; 2, lateral view. (Length, rostrum excluded = 6.3 mm).

FIGURES 4-5: Pacholenus monteiroi sp. nov., head, lateral views; 4, male holotype; 5, female paratype. (Scale = 0.5 mm).

FIGURES 6-7: Pacholenus monteiroi sp. nov., aedeagus of holotype; 6, lateral view; 7, dorsal view. (Scale = 0.2 mm).