New combination and new synonymy in the tribes Megalonotini and Lethaeini (Hemiptera: Rhyparochromidae)

Nueva combinación y sinonimia en las tribus Megalonotini y Lethaeini (Hemiptera: Rhyparochromidae)

Dellapé Pablo, M. and María del Carmen Coscarón

División Entomología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, Paseo del Bosque. 1900 La Plata, Argentina; e-mail: pdellape@museo.fcnym.unlp.edu.ar; coscarón@netverk.com.ar

ABSTRACT. The syntypes of Lamprodema inerme Berg a Megalonotini, deposited in the collection of Museo de La Plata (Argentina) are examined and   transferred to the monotypic genus Stictolethaeus O´Donnell in the tribe Lethaeini as Stictolethaeus inerme (Berg) (new combination) and Stictolethaeus slateri O´Donnell is treated as a junior synonym of Lamprodema inerme (new synonymy). The absence of inner laterotergites in the macropterous syntype reveals that further studies are needed in order to establish the correct position of Stictolethaeus inerme within a tribe.

KEY WORDS. Rhyparochromidae. Lethaeini. Megalonotini. Stictolethaeus inerme. New combination.

RESUMEN. El material tipo de Lamprodema inerme Berg, un Megalonotini, depositado en la colección del Museo de La Plata (Argentina) es examinado y la especie es transferida al género monotípico Stictolethaeus O´Donnell en la tribu Lethaeini como Stictolethaeus inerme (Berg) (nueva combinación) y Stictolethaeus slateri O´Donnell es relegada a sinónimo junior de Lamprodema inerme (nueva sinonimia). La ausencia de laterotergitos internos en el único ejemplar macróptero conocido revela que son necesarios más estudios para establecer la correcta ubicación de S. inerme.

PALABRAS CLAVE. Rhyparochromidae. Lethaeini. Megalonotini. Stictolethaeus inerme. Nueva combinación.

Lamprodema inerme Berg 1883, the unique species of the tribe Megalonotini presently known in the Neotropical region (Lethierry & Severin, 1894; Pennington, 1921; Slater, 1964) was originally described based on one macropterous male and one coleopteroid female collected by Félix Lynch Arribálzaga in Chacabuco, Buenos Aires province, Argentina (Berg, 1883).

Subsequent publications, such as “Zoogeography of the Rhyparochrominae” (Slater, 1986) and “True Bugs of the World” (Schuh & Slater, 1995), ignored the presence of this species in the Neotropics. Moreover, Slater considered that the species does not belong to Lamprodema Fieber, and consequently that the tribe is not represented in this region (pers. comm).

In order to clarify the generic position of L. inerme we examined its syntypes, as well as an additional male specimen from the Argentina, province of Entre Ríos, also deposited in the collection of Museo de La Plata, Argentina. In the end we determined that the species belongs to the monotypic genus Stictolethaeus O´Donnell 1991 in the tribe Lethaeini, Stictolethaeus inerme (Berg 1883) (new combination), and Stictolethaeus slateri O´Donnell 1991 is relegated to a junior subjective synonym of Lamprodema inerme (new synonymy). For this reason, in accordance with Slater (1986) and Schuh & Slater (1995), we consider that the tribe Megalonotini has no representatives in the Neotropical region.

Stictolethaeus was described by O´Donnell (1991) to include S. slateri which exhibits several distinctive morphological characters, including a highly modified, unique genitalia and unusual sexual dimorphism. She studied 236 coleopteroid female and male specimens from several places in Argentina (Buenos Aires, Catamarca, Córdoba, and Santa Fe provinces) and Uruguay (Maldonado, Montevideo, Paysandú, and Rocha departments), pointing out that “features associated with coleoptery include loss of the hind wing, desclerotization of the anterior tergites in the female and perhaps the loss of inner laterotergites”.

The macropterous syntype of L. inerme examined during the present study lacks inner laterotergites, as it is usual in coleopteroid forms. Because the presence of inner laterotergites is characteristic of the tribe Lethaeini, this finding reveals that further studies are needed in order to establish the correct position of Stictolethaeus inerme within a tribe. Finally, the macropterous male is herein designated as lectotype and the female specimen as paralectotype.

Our gratitude to G. Spinelli (División Entomología, Facultad de Ciencias Naturales y Museo, UNLP) for his critical reading of the manuscript.

LITERATURE CITED

1. BERG, C. 1883. Addenda et emendata at Hemiptera Argentina. Anal. Soc. Cient. Argent. 15(6): 241-269.         [ Links ]
2. LETHIERRY, L. & G. SEVERIN. 1894. Catalogue général des Hémiptères. Musée Royal d'historie Naturelle de Belgique. 2: 277 pp.         [ Links ]
3. O´DONNELL, J. E. 1991. A new coleopteroid lethaeine from southern south america (Hemiptera: Lygaeidae: Rhyparochrominae). J. New York Entomol. Soc. 99(3): 87-96.         [ Links ]
4. PENNINGTON, M. S. 1921. Lista de los Hemípteros Heterópteros de la República Argentina. Buenos Aires 2:17-18.         [ Links ]
5. SCHUH, R. T. & J. A. SLATER. 1995. True Bugs of the World (Hemiptera: Heteroptera): Classification and Natural History. Cornell University Press, Ithaca and London. Storrs.         [ Links ]
6. SLATER, J. A. 1964. A Catalogue of Lygaeidae of the World. Cornell University Press. Storrs.         [ Links ]
7. SLATER, J. A. 1986. A synopsis of the zoogeography of the Rhyparochrominae (Heteroptera: Lygaeidae). J. New York Entomol. Soc. 94(2): 262-280.         [ Links ]

Recibido: 17-IX-2003
Aceptado: 15-I-2004