1. Introduction

Unlike numerous Heteroptera described from the contemporaneous Dominican amber, there are only few taxa recorded so far from Mexican amber: Ceratocombus hurdi (^{Wygodzinsky, 1959} - Dipsocoridae); Leptosalda chiapensis (^{Cobben, 1971} - Leptosaldidae); Amnestus guapinolius (^{Thomas, 1988}- Cydnidae); Empicoris electricus (^{Thomas, 1992}- Reduviidae); Termitaradus protera (^{Poinar and Doyen, 1992}- Termitaradidae); Stenohebrus glaesarius (^{Polhemus 1995}- Hebridae) and Miridae (Isometopinae), Aradidae, Dipsocoridae and Hebridae mentioned but not described by ^{Hurd et al (1962)}, (^{Poinar, 1992}, ¹⁹⁹⁹; ^{Grimaldi, 1996}; ^{Poinar and Heiss, 2011}; ^{Solórzano-Kraemer, 2007}, ²⁰¹⁰).

The Mexican amber of Simojovel in the state of Chiapas originated and was formed by resin of the fossil Leguminosae tree Hymenaea mexicana (^{Poinar and Brown, 2002}). Still controversial is the age; older deposits are estimated to be from the late Oligocene with an age of 22.5-26 Mya (^{Berggren and Van Couvering, 1974}; ^{Poinar, 1992}), and younger deposits from the mid Miocene with an estimated age of 15-20 Mya (^{Iturralde-Vinent and MacPhee, 1996}; ^Poinar,1999; ^{Solórzano Kraemer, 2007}, ²⁰¹⁰). The latter date seems to be presently accepted.

Among Aradidae, the Neotropical genus Calisiopsis (^{Champion, 1898}) of the subfamily Calisiinae (^{Stål, 1873}) contains to date seven species, six of them are extant described from Panama (C. ampliceps ^{Champion, 1898}), Peru (C. kormilevi ^{Froeschner, 1992}), Mexico (C. minutus ^{Kormilev, 1959} from Tampico, C. nigrotuberculata ^{Froeschner, 1992} from Laredo), Brazil (C. brasiliensis ^{Kormilev, 1956}; C. planiceps ^{Kormilev, 1976}) and one fossil from Dominican amber (C. brodzinskyorum ^{Froeschner, 1992}).

Calisiopsis is characterized by the small size, the wide head and short antennae, segment IV usually as long as the preceding ones together. A key to these seven species was given by ^{Froeschner (1992)}. The now described Calisiopsis azteca n.sp. from Mexican amber resembles and seems more closely related to C. brodzinskyorum from Dominican amber, supposedly of the same age and plant origin as both extant taxa recorded from Mexico.

2. Materials and Methods

The specimen is enclosed in a piece of transparent honey-colored Mexican amber, which will be embedded later in epoxy resin for better conservation. It is complete with legs and antennae bent ventrally that are obscured by impurities and only partly visible. A small bee is found as a syninclusion.

Photo was taken using an Olympus SZX 10 binocular microscope with an attached Olympus E 3 digital camera and processed with Helicon Focus 4.3 software and using Adobe Photoshop and Lightroom 2.3.

Measurements were taken with a micrometer eyepiece and are given in millimeters. Abbreviations used: deltg = dorsal external laterotergite (connexivum).

When citing the text on the labels attached to the specimen / separates the lines and // separates different labels.

3. Taxonomy

Family Aradidae ^{Brullé, 1836}

Subfamily Calisiinae ^{Stal, 1873}

Genus Calisiopsis ^{Champion, 1898}

Calisiopsis azteca n.sp.

(Figures 1,^3,4)

Figure 1-2 Fossil Calisiopsis spp. (1) Calisiopsis azteca n.sp., reconstruction of habitus; (2) Calisiopsis brodzinskyorum , after ^{Froeschner (1992) Fig.4}. Scale 1 mm. 

Figure 3 Calisiopsis azteca n.sp., inclusion in Mexican amber. 

Holotype. Macropterous female in Mexican amber, designated as holotype with the attached label: Holotype /Calisiopsis / azteca n.sp. / des. E.Heiss 2014 //. Preserved as MA-Ca-01 in the collection of the author at the Tiroler Landesmuseum.

Diagnosis. Small elongate species with denticulate lateral margins of pronotum without elevated blunt tubercles between median carina and lateral margins of scutellum. Resembles Calisiopsis brodzinskyorum from Dominican amber but differs by more elongate habitus, different head structure and the presence of 4 lateral tubercles on lateral margin of deltg II-VII and further characters discussed later.

Description. Color. Light brown with whitish (secondary) incrustation on head, pronotum and scutellar elevations.

Head. Wider than long (0.6/0.45); clypeus with a dorsolateral row of 6 and beneath a lateral row of 4 spine-like tubercles; antenniferous lobes large and bidentate, antennae short, about as long as head, antennal segments I-III moniliform, IV elongate, as long as the three preceding ones together; eyes small hemispherical, postocular lobes acute, slightly protruding over outer margins of eyes, then straightly converging to constricted neck; vertex with a double row of larger tubercles at middle, a row of 4 lateral tubercles along the eyes and about 5 tubercles delimiting the posterior margin medially from neck; rostrum arising from a slit-like atrium as long as head.

Pronotum. More than twice as wide as long (0.95/0.45); lateral margins straightly converging anteriorly, beset with about 11 spine-like tubercles; anterior margin straight, posterior margin sinuate at middle; disk with 4 granulate carinae, the 2 median ones are longer reaching to anterior margin, the 2 lateral ones shorter not exceeding the transverse impression; surface finely punctate.

Scutellum. Elongate, 1.4x as long as wide (1.2/0.85); lateral margins beset with a row of larger tubercles, excavated on anterior half for the reception of the carinate visible costal margin of hemelytra; basal triangular elevation with 4 larger tubercles overlapping pronotum, surface granulate; median carina with a double row of tubercles extending posteriorly, joining tuberculate posterior margin; surface between median carina and lateral margin punctate and finely granulate without larger elevated tubercles.

Abdomen. Of oval shape, slightly reflexed lateral margins of deltg II-VII with 4 blunt tubercles, surface punctured; venter finely punctate.

Measurements. Length 2.4mm; width of abdomen across tergite III 1.25mm.

Etymology. Named after the Aztec people, who developed the great Mesoamerican native civilisation destroyed in the 16^thcentury by Spanish conquerors.

4. Discussion

The only fossil representative of the extant Calisiinae genus Calisiopsis (^{Champion, 1898}) is C. brodzinskyorum (^{Froeschner, 1992}) described from contemporaneous Dominican amber (^Figure2). Comparison of C. azteca n.sp. with the original description and the illustration (Figure 4) of C. brodzinskyorum shows following differences: