A new record from insular Chile for the Neotropical and Andean cydnid Melanaethus spinolae (Signoret, 1864) is presented. Specifically, the new record comes from Easter Island, making M. spinolae the first burrower bug found in this Oceanic island. The possible causes of the range expansion of this taxon are commented.
Se presenta un nuevo registro del cídnido andino y neotropical Melanaethus spinolae (Signoret, 1863) para Chile insular. El nuevo registro proviene específicamente de Isla de Pascua, convirtiendo a esta chinche en el primer cídnido para esta isla oceánica. Se comentan las posibles causas de la expansión de este taxón.
Cydnidae, commonly known as burrower bugs, is a large family of heteropterans with more than 850 species classified in six subfamilies: Amaurocorinae, Amnestinae, Cephalocteinae, Cydninae, Garsauriinae and Sehirinae (Rider et al., 2018).
Cydnines are usually recognized for their bright black coloration and size ranging from small to medium (Froeschner, 1960). Among cydnines, Melanaethus Uhler, 1876 is a New World genus which contains the smallest species of the subfamily, currently containing 18 species (Mayorga, 2002; Schwertner & Nardi, 2015).
Melanaethus spinolae (Signoret, 1864) was described from continental Chile (without any specific location); however besides its description, no additional information was provided. Subsequently, it has been recorded from Panamá, Dominican Republic, British Guyana, Brazil, Paraguay and Argentina (Froeschner, 1960; Schwertner & Nardi, 2015; Coscarón, 2017). While M. spinolae is a widespread species, nothing is known about its biology or economic importance, as for many other South American Cydnidae (Schwertner & Nardi, 2015). The purpose of this contribution is to provide a new record of this species in Insular Chile.
Specimens were identified following Froeschner (1960) and Schwertner & Nardi (2015) and treated with Barber's solution to clean and manipulate. Photos were taken with a digital camera Ricoh 550® adapted to a Celestron 44202® stereoscopic microscope. All material is deposited in the collection of the Instituto de la Patagonia, Universidad de Magallanes, Punta Arenas, Chile.
After the original description (Signoret, 1864), the only additional record for M spinolae in Chile, from Valparaiso (Central Chile, 33.0472° S, 71.6127° W), was published by Reed (1898). Here we provide the first record from Oceanic Chile, from Easter Island:
Material Examined (Fig. 1). Chile, Valparaiso Region, Hanga Roa, Easter Island, 27.1500° S, 109.4333° W, X-2016, floating in a pool, 2 ♀♀, F. Ramirez, Leg.
Habitus of <italic>Melanaethus spinolae</italic> (<xref ref-type="bibr" rid="ref-8-e120">Signoret, 1863</xref>) specimen from Hanga Roa.
Fig. 1.— Hábitus del ejemplar de Melanaethus spinolae (Signoret, 1863) de Hanga Roa.
Easter Island, although belonging administratively to Valparaiso Region, is in the middle of the Pacific Ocean, 4254 km away from Continental Chile. This is the inhabited place in the world most isolated in the sea, but high touristic inflow may have facilitated the recent arrival of M. spinolae from Continental Chile (Fig. 2).
Distribution of <italic>Melanaethus spinolae</italic> (<xref ref-type="bibr" rid="ref-8-e120">Signoret, 1863</xref>) in Chile. Red square = known distribution, blue square = new record.
Fig. 2.— Distribución de Melanaethus spinolae (Signoret, 1863) en Chile. Cuadrado rojo = distribución conocida, cuadrado azul = nuevo registro.
There are no previous records of burro wer bugs from Easter Island (Campos & Peña, 1973). Thus M. spinolae becomes the first species of Cydnidae recorded in this area. Further surveying is needed to assess the establishment of this species in this remote environment.
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