Acyphus renggeri (Labram & Imhoff)

Lanteri, Analia A. & Rio, M. Guadalupe Del, 2006, Taxonomic revision of the monotypic genus Acyphus Heller (Coleoptera: Curculionidae) with comments on infraspecific variation, Zootaxa 1312, pp. 59-68 : 64-67

Acyphus renggeri (Labram & Imhoff)

Megalostylus renggeri Labram & Imhoff 1849 : Nº 61; Dalla Torre et al. 1936:10 (catalogue); Blackwelder 1947:792 (checklist).

Acyphus renggeri: Kuschel in Wibmer & O’Brien 1986:52 (checklist).

Acyphus funicularis Heller 1921:27 (syn. by Kuschel in Wibmer & O’Brien 1986:52)

Redescription. Species medium sized (female 9.50–15.50 mm long; male 8.60–9.75 mm long). Integument black to dark­brown, shiny, either devoid of distinct scaly vestiture, or covered with cream, oval, apressed scales. Antennae clothed with fine white setae and dark­brown stiff, verticillate setae at distal end of each funicular article. Pronotum with three longitudinal stripes (one slender, along midline, and two wide, on sides). Scutellum squamose, white. Elytra with three different types of vestiture: A) with distinct oval scales, forming a nebulose pattern on whole disc and two pairs of more dense irregular maculae on each side of suture, one near middle and other on posterior declivity ( Fig. 1 ); with distinct oval scales forming a nebulose pattern but lacking pairs of more dense irregular maculae ( Fig. 2 ); and lacking distinct scaly vestiture (except on apical border), but with minute round pale­blue scales, only visible with high magnification ( Figs. 3–4 ). Metepisterna completely covered with white scales. Legs and venter covered with setalike scales and scatter suberect setae. Rostrum (LR/WR:1.15–1.33; WF/WR:1.52–1.70). Pronotum (WP/LP:1.37–1.57; WP+/WP­:1.20–1.45). Elytra (LE/WE:1.48–1.68). Other morphological features of females and males as those described for the genus ( Figs 1–13 ).

Type material studied. 1 female probable syntype of Acyphus funicularis , at the Bruch collection ( MACN): [Rca. Argentina / Prov. Santa Fe 1913/ C. Bruch] [Rosario Hubrig Leg.]

Type of Megalostylus renggeri not seen. According to Kuschel (1955) the Imhoff´s collection of types should be at the Museum of Bassel, Switzerland, but the type of Megalostylus renggeri was not found there.

Other material studied. ARGENTINA. Buenos Aires: no loc., Viana col. (2 AMNH); Isla Martín García, Viana col., 26–29­I­1938 (97 MLPC), IV­1938 (1 CWOC, 3 MACN); Tigre, XII­1950 (1 MLPC). Chaco: Las Delicias, 15­III­1936, Denier col. (1 MLPC); Fontana, 8­XI­1935, Denier Col. (3 MLPC), XII­1935 (2 MLPC); Dep. Resistencia, 23­II­1939 (1 MLPC), X­XII­1935, Daguerre col. (1 CWOB, 2 MACN). Córdoba: Dto. Calamuchita, El Sauce, 1939­1942, Viana col. (2 MLPC), I­1953 (1 MLPC); Dto. Punilla, Valle Hermoso, XII­1942 (6 MLPC). Entre Ríos: no loc., I­1970, Vera Bezzi col. (2 MLPC); Concordia (1 MACN); Puerto Liebig, I­1963 (1 USNM); Ruta 12, 35mi S. Gualeguaychú, 16­XII­1976, on Prosopis algarrobilla (1 USNM). Formosa: Isla Oca, 1­II­1938 (2 MLPC), 8­I­1939 (2 MLPC), 1­II­1939 (9 MLPC); Clorinda, 14­II­ 40 (1 MLPC), 15­X­1937, col. Denier (2 MLPC); Formosa, II­1949, Martinez leg. (9 MZSP); Ruta 81, 1mi N.W. Formosa, 10­XII­1976, on Prosopis algarrobilla (1 USNM). Misiones: Dto. Concepción, Santa María, X­1944 ­48 (8 MLPC). Salta: Metán, 13­I­1948 (3 FIML); Pocitos, 24­26­XI­1954 (1 MLPC). Santa Fe: no loc. (3 MLPC, 2 MACN); Arroyo Pindo V. Ocampo, 2­II­1948 (1 FIML); Laguna Quebracho, II­1962 (1 MLPC); Villa Ana, 1­18­II­1946 (3 FIML); Villa Guillermina, 15­26­II­1948 (1 FIML). Santiago del Estero: Fortín Inca, 20­XII­1937 (9 MLPC). Tucumán: no loc. (7 BMNH, 1 MACN); Tapia, XI­1912 (1 MACN). BRAZIL. Rio de Janeiro: Guaratiba, VIII­1941, Aristoteles Silva (1 MLPC). PARAGUAY. San Lorenzo, 13­I­1939, Denier col. (1 MLPC). URUGUAY. Artigas: Rio Puareim, Picada del Negro Muerto, Sepulturas, 15­I­1952, C. S. Carbonel (1 CWOB). Río Negro: San Javier (1 CWOB, 1 MLPC), I­1938 (2 MLPC).

Geographic distribution. Acyphus renggeri was originally cited only for Santa Fe province, Argentina. Based on the material studied we add several new locality records and confirm its occurrence in ten Argentinian provinces, Paraguay and Uruguay. Regarding to Brazil, we suspect that the species is distributed in the southern states (Paraná, Santa Catarina and Rio Grande de Sul) but we were not able to confirm it presence in this country. The only specimen studied from Brazil came from Guaratiba (Río de Janeiro state), a locality far out of the range of Acyphus and its host plants within the genus Prosopis . For this reason we consider that the locality label of that specimen housed at the MLPC must be wrong and we cited it under the material studied with doubts.

Infraspecific variation. The variation of A. renggeri is mainly related to the presence and distribution of the elytral scales. According to it, there are three main patterns or morphotypes: A) nebulose scaly pattern with two pairs of dense irregular maculae ( Fig. 1 ); B) similar to the former but lacking pairs of dense irregular maculae ( Fig. 2 ); and C) lacking distinct scaly vestiture ( Figs. 3–4 ). The first morphotype was seen in females from Córdoba, Misiones, Santa Fe, Santiago del Estero and Tucumán ( Argentina); the second corresponds to females from Argentina (Buenos Aires, Chaco, Entre Ríos, Formosa, Salta, Santa Fe and Santiago del Estero) Paraguay and Uruguay; and the third morphotype was recorded for males and females from Formosa ( Argentina) (see figure 14). Morphotypes A and B coexist in Santa Fe and Santiago del Estero ( Argentina), whereas B and C occur in Formosa ( Argentina). It seems that the scaly vestiture becomes looser in northern direction, and in some instances (e.g. samples from Chaco) there are specimens with intermediate patterns (e.g. between B and C). It is also remarkable that males are only known from Formosa and they are all devoid of scales.

The presence of several populations composed only by females and a single population from Formosa ( Argentina) with the presence of both sexes, would suggest a phenomenon of geographical parthenogenesis ( Lanteri & Normark 1995). This kind of reproduction is also recorded for other species of Naupactini with similar distribution and it should be confirmed by further biological studies and/or molecular analyses ( Normark & Lanteri 1998; Scataglini et al. 2005).

Figures

FIGURES 1 – 4. Dorsal habitus of Acyphus renggeri. 1 – 3, females; 4, male. Scale: 2 mm.