The genital capsule in Anomalini

The aedeagus (Fig. 1a–b) in the American species of Anomalini (without considering the internal sac) is characterized by the following configuration of its parts:

TEGMEN. Subcylindrical and robust in shape, with a moderately to broadly convex lateral profile; the parameres almost always shorter than the basal piece. The relative position between the parameres and the tectum with various degrees of angulation, from aligned in most genera (Fig. 1a, c, e, g, i, k), to perpendicular (Fig. 3).

BASAL PIECE. Moderately sclerotized and symmetrical, with wide variation in length (Fig. 1c, g). The dorsum and laterals are moderately to highly sclerotized and the ventral side closed by the median lobe with different degrees of sclerotization, from a partially translucent thin surface ( Leptohoplia in Fig. 2) to a highly sclerotized plaque ( Dilophochila in Fig. 2).

PARAMERES. Consist of a pair of structures with the greatest morphological variation, but with interspecific consistency (Fig. 1b, d, f, h, j, l). They are articulately attached to the phallobase and are symmetrical in the vast majority of American species, as well as with notable simplification in the development and complexity, with certain exceptions, where they can be very complex and long. [e.g., Paranomala doryphorina (Bates, 1888) (Fig. 1k–l), etc.]. Dorsally they may be separate (Fig. 1j), contiguous, or basally (Fig. 1d, h) or completely overlapping (Figs 1f, 4e), while ventrally they are independent and completely separated (Fig. 1l, and as Strigoderma, Lamoana and Dilophochila in Fig. 2), nearby (as in Epectinaspis and Yaaxkumukia in Fig. 2), or even fused with the median lobe forming a ring (as in Callistethus and Pachystethus in Fig. 2).

MEDIAN LOBE. A plate that covers the ventral face. It presents various degrees of sclerotization, from a translucent membranous plate without apical development (as in Leptohoplia (Fig. 2) and some species of Paranomala), up to a strong plate with great apical development that projects to the apex of the parameres (Figs 1k–l, 3, 4a, c, g–h) (as in Lamoana and Dilophochila in Fig. 2). In most genera, the apical end is absent, converging with the ventral base of the parameres with little variation (as Paranomala in Fig. 2), but in a few cases it can also present great diverse morphological expressions, such as asymmetrical extensions (Fig. 1c–d), or a complex tubular or subtriangular elongated shape (Figs 1l, 3c).

In general terms, it is possible to recognize a configuration pattern of the tegmen at the genera level, whose own modifications of the basal piece, parameres and median lobe are congruent and constant, as outlined below.

The free parameres, in vertical position, generally simple apices and aligned with the tectum, in close contact with the median lobe, both on the apex and on the lateral faces are typical of the genera Leptohoplia and Paranomala (Fig. 2); however, it is important to note that Paranomala is a polyphyletic taxon (Ramírez-Ponce & Morón 2009), so the numerous exceptions may be due to species related to other lineages.

The parameres in vertical position, fused partially or totally with the median lobe forming a ring, and the later partially fused with the basal piece are characteristic of the genera Callistethus, Pachystethus and Xochicotlia (Fig. 2). The genus Callistethus presents problems in its morphological delimitation and sometimes species of other genera are included, but have a different genital morphology (e.g., see Filippini et al. 2015). Additionally, it is a Pantropical genus, with a huge taxonomic problem in tropical Asia.

The parameres with the distal portion arranged dorsoventrally, contiguous ventrally and with the median lobe, and clearly separated from the basal piece, with the median lobe short, only developed to the base of the parameres, characterizes the genera Epectinaspis and Yaaxkumukia . Both genera have taxonomic treatments (Paucar-Cabrera 2003; Micó et al. 2006).

The monotypic genus Nayarita presents subcylindrical parameres with forceps-like apex, and moderately separated from each other ventrally, with the median lobe free (Fig. 2). It is an unusual shape compared to the rest of all the tribe.

The genus Strigoderma presents generally simple parameres with the distal portion in a dorso-ventral arrangement in most species (Fig. 1i), and always separated ventrally (Figs 1j, 2, 7b–f). The median lobe is subcylindrical, moderately sclerotized, and separated from the parameres and ventral plate (Fig. 7b–f). There is a revision of the genus (Bader 1992), although the morphological limits remained ambiguous both in the characterization of somatic and genital morphology. Some species with perpendicular parameres have frequently been classified in this genus, although one species, S. guatemalicus Katbeh-Bader, 2000 has the parameres markedly angulate, but neither perpendicular nor dorsoventrally depressed (Katbeh-Bader 2000).

The parameres arranged dorsoventrally, with a perpendicular position with respect to the tectum (Fig. 3), are a morphological pattern that also constantly presents sub-laminar parameres, vestiture, and are widely separated in the ventral face, with a widely projected sub-triangular median lobe that reach the apex of the parameres (Fig. 4). This type of tegmen is presented by the genera Balanogonia, Callirhinus, Mazahuapertha and Moroniella (Figs 5–6), whose species also present anthophagous habits (for Mazahuapertha, its natural history is unknown). Diverse species with these genitalia have frequently been classified in Strigoderma (e.g., Bates 1888; Bader 1992), as in the case of S. villosella, although the somatic (Figs 5a, 6a) and sexual differences (i.e., the shape and position of the parameres, and the unique median lobe), do not justify such an affinity (Fig. 7a).

The genus Dilophochila is atypical in its morphology with respect to the entire tribe (Fig. 6e). The parameres are angled respect to the tectum, though not reaching a perpendicular position. Also, they are subcylindrical in the basal half and widely separated on their ventral side. The median lobe is remarkably long, subtriangular, and completely separated of both the parameres and the basal piece (Fig. 2). There is a revision of the genus (Morón & Howden 2001).