The nymph of Anisagrion Selys 1876, based on the discovery of A. inornatum (Selys, 1876) in Ecuador (Odonata: Coenagrion
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ORIGINAL ARTICLE
The nymph of Anisagrion Selys 1876, based on the discovery of A. inornatum (Selys, 1876) in Ecuador (Odonata: Coenagrionidae) Kenneth J. Tennessen
Received: 20 October 2011 / Accepted: 14 March 2012 # Gesellschaft für Biologische Systematik 2012
Abstract The final instar nymph of Anisagrion inornatum is described and illustrated based on five specimens (one reared) from southern Ecuador. It is the first to be discovered for the genus. The nymph of Anisagrion inornatum differs from its closest relative, Apanisagrion lais, by: (1) antenna shorter in relation to head length (ratio 1.35 in An. inornatum vs 1.55 in Ap. lais); (2) fewer palpal and premental setae (5 palpal and 4 or 5 premental setae in An. inornatum vs 6– 8 palpal and 5–8 premental setae in Ap. lais); (3) venter of S3–S8 with medial dark stripe. The nymphs were found in a slow shallow seep overgrown with emergent wetland plants. Keywords Zygoptera . Anisagrion . Nymph Abbreviations S1–10 Abdominal segments 1 through 10 antm Antennomere
Introduction Of the 50 genera of New World Coenagrionidae (Zygoptera), 24, i.e., nearly half, are unknown in the nymph stage (see Garrison et al. 2010); all of the unknown genera are Neotropical and most occur only in South America. Anisagrion Selys, 1876, which is known from southern Mexico to Panama, Venezuela and Ecuador, is one of the unknown genera, as the nymph of none of the four species has been previously discovered. I collected several specimens of Anisagrion inornatum (Selys, 1876) in K. J. Tennessen (*) Florida State Collection of Arthropods, 125 N Oxford St, Wautoma, WI 54982, USA e-mail: [email protected]
Loja Province in southern Ecuador, March, 2008. The following description, the first for the genus, is based on five final instar nymphs (one male emerged 3 April 2008). Methodology Drawings of mouthparts and abdominal segments were made with aid of a camera lucida. Caudal lamellae were slide-mounted and photographed with a Nikon D700 digital camera mounted on a Wild stereomicroscope. Measurements (mm) were made with a calibrated ocular micrometer at various magnifications. Head length was measured from anterior-most margin of right compound eye to posterior-most margin of right postero-lateral lobe. Mandibular formula follows Watson (1956). Prementum length (excluding hinge) and width are maximum dimensions. Abdomen length and total length were measured only on unreared nymphs, with each abdominal segment partly telescoped into the preceding segment, approximating the living condition; these measurements do not include cerci or caudal lamellae. Segment 10 (S10) was fully extended and its length was measured dorso-medially. Four specimens are deposited in the Florida State Collection of Arthropods, one in the Colección Entomológica del Instituto de Ecología, A.C., Xalapa, Mexico.
Description of final stadium nymph of Anisagrion inornatum Relatively stocky nymph, medium brown, head mottled with tan, legs tan, abdomen appearing granular except on
K.J. Tennessen
two submedian p
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