Amara Curtonotus Stephens, 1827

Li, Yihang, Li, Haoyuan & Shi, Hongliang, 2024, Revision of the macropterous subgenus Curtonotus from east China, with the description of a new species (Carabidae, Zabrini, Amara), ZooKeys 1190, pp. 39-73 : 39

Subgenus Amara Curtonotus Stephens, 1827

Type species.

Amara convexiuscula (Marsham, 1802); type locality: “England”.

The subgenus Amara Curtonotus is recognizable among genus Amara by the combination of the following characteristics: 1) medium to large sized species (7-25 mm); 2) prosternal process not bordered, without setae at apex; 3) inner margin of male mesotibiae with projection in most species (present as one to three distinct denticles); 4) right paramere without a terminal hook; 5) pronotum more or less cordate, constricted to base, distinctly narrower than elytral base; 6) mesofemora mostly with only two posterior setae.

The subgenus Amara Curtonotus was regarded as the most basal clade of the tribe Zabrini ( Sánchez-Gea et al. 2004), but the intra-group relationships among the species of Amara Curtonotus are still unclear. Amara Curtonotus is similar to the subgenera Bradytulus Tschitscherine and Tibetamara Makarov & Sundukov in external appearances ( Hieke 2010; Makarov and Sundukov 2021). The subgenus Amara Bradytulus is different from Amara Curtonotus by the generally much smaller body size, prosternal process with reduced border, and male metatibiae mostly with tufted ensiform setae. Tibetamara is different from Amara Curtonotus by the male mesotibiae without a projection, right paramere shortened, and a relatively wide pronotum base. Some large species of the subgenus Amara Bradytus may also be similar to Amara Curtonotus but can be distinguished by prosternal process bordered, grooves of pronotum basal fovea shorter and usually shallower, and the right paramere usually with an apical hook. The subgenera Amathitis Zimmermann, Ammoleirus Tschitscherine, Cribramara Kryzhanovskij, Harpalodema Reitter, and Hyalamara Tschitscherine also have a constricted pronotum base, but can be readily distinguished from Amara Curtonotus by having multiple setae on the mesofemora.

Amara Curtonotus species can be found in various open habitats, including grassland, alpine meadow, coastal areas, riparian flood plains, riverbanks, and forest margins. Throughout our observations, we noted that many inhabit similar environments together with other Amara and Harpalus Latreille species. Both adults and larvae of Amara Curtonotus demonstrate omnivorous feeding habits, consuming other insect larvae as well as plant seeds ( Sasakawa 2010). Among them, species like A. (C.) gigantea Motschulsky, 1844 are aggressive predators. Macropterous species can be attracted by light sources, and some species climb on stalks or leaves for foraging. Certain widely distributed species, like A. (C.) gigantea and A. (C.) macronota , are commonly found in urban areas and agrarian lands, suggesting potential roles in pest and weed control ( Sasakawa 2009). Moreover, other species such as A. (C.) brevicollis Chaudoir, 1850, A. (C.) dux Tschitscherine, 1894, and A. (C.) fodinae Mannerheim, 1825 have also been recorded in proximity to residential areas.

According to Hieke’s (2010) work, the Chinese Amara Curtonotus species were classified into two groups, mainly based on the shape of metepisternum. Group A includes the macropterous Amara Curtonotus , with hind wings usually well developed (rarely shortened), metepisternum long, with length on outer margin nearly twice as long as the anterior width. Most species of this group have widespread distributional ranges, more commonly seen in the northern and eastern provinces of China. The Group B contains brachypterous Amara Curtonotus , with hind wings usually rudimentary (rarely shortened); metepisternum short, with length on outer margin subequal to the anterior width. Most species of this group are narrowly distributed, only known from the high mountain areas of west China.

In the present paper, we focus on the macropterous Amara Curtonotus from the eastern provinces of China with describing a new species and providing supplementary notes on all other species so far recorded in this area. Based on available materials, four species groups of the macropterous Amara Curtonotus were recognized in the eastern China: Amara gigantea group, Amara tumida group, Amara brevicollis group, and Amara macronota group, mainly based on the characteristics of head size, number of supraorbital setae, shape of pronotum, male mesotibiae projection, and the apex of male genitalia. Other Amara Curtonotus species not recorded from this area may have relationships with some of the above species groups, but they have not been treated in the present paper.