Amara (Tibetamara), Makarov & Sundukov, 2021

Makarov, Kirill V. & Sundukov, Yurii N., 2021, A new subgenus of the genus Amara Bonelli, 1810 (Coleoptera: Carabidae) from northeastern Tibet, China, Zootaxa 5057 (2), pp. 228-240 : 229-236

Tibetamara Makarov et Sundukov, subgen. n.

Type species: Amara validula Tschitschérine, 1898 , designated herewith.

Species composition. Amara validula Tschitschérine, 1898 .

Diagnosis. Body robust, rather large (10–11 mm), dark; antennae monochromous, reddish.

Head: two supraorbital pores; mentum tooth well-developed, bifid.

Prothorax: relatively large, transverse (about 1.5 times as wide as long), slightly trapezoidal, with two basal foveae on each side; outer basal fovea with a distinct lateral fold reaching the basal margin; two lateral setae; posterior angles distinct, pointed. Propleuron and prosternum punctate; prothorax of male and female of similar structure except punctuation being more or less strongly and longitudinally depressed between coxae. Prosternal intercoxal process not marginated and asetose apically.

Elytra: relatively short, only 1.3 times as long as wide, moderately convex; shoulder angle distinct, with a tooth; parascutellary pore absent; striae punctate; stria 7 with one preapical setiferous puncture.

Ventral side of meso- and metasterna densely and coarsely punctate.

Abdomen: sternites III–V each with one pair of setae; anal sternite with 2–4 setae in males and 4 setae in females.

Legs: claws long and slender; apical spur of protibia simple; dorsal side of protibia with 4–6 setae; middle femur with 2 setae along posterior margin; mesotibia in males with a row of small tubercles on inner side; metatibia of male on inner side with one additional row of rather long setae on apical third. Ventral sides of meso- and metatarsomeres 1–3 with lateral rows of long bifid or trifid setae (Figs 13, 14), this resulting in apical quarter of plantar surface of these tarsomeres and being entirely clothed with setae. At least some of the apical setae longer than apical width of tarsomere.

Aedeagus: median lobe without groove on right side; lamella long, narrow, tapering towards apex; right paramere robust, short, without apical hook.

Position within the genus. The subgeneric division of the genus Amara ( Andrewes 1930; Bates 1873; Hieke 1978, 1983, 1990, 1994, 1999a, 2001, 2003c, 2005, 2006, 2012; Jeannel 1942; Lutshnik 1935) is mainly based on the chaetotaxy of the prothoracic process, legs, and abdominal sternites; the presence or absence of margination at the tip of the prothoracic process; the number of preapical setiferous punctures in elytral stria 7; the structure of the apical spur of the fore tibia; the sculpture and chaetotaxy of the middle of the prothorax, middle and hind tibiae in male; the shape and structure of the pronotum; the colour of the antennae; the presence or absence of a scutellary pore on the elytra; the structure of the aedeagus median lobe and right paramere in males, and of the gonostyles in female.

However, most of the characters listed above demonstrate similarities in different subgenera or are variable within one subgenus. As a result, there are exceptions or species with a transitional combination of features in almost every subgenus, this often complicating their identification. In his first works on the genus Amara, Hieke (1978) already expressed cautiously the idea that we observe many characters of the subgenera and groups of species in Amara in the process of their formation. Therefore, features characteristic of all members of one subgenus can be found in other subgenera, albeit weakly expressed. A character such as a fovea on the male prothorax, which is characteristic of the subgenera Xenocelia , Pseudocelia , Camptocelia, Cumeres , Bradytus etc., exceptionally occurs in the nominative subgenus as well ( Hieke 2002); the parascutellar pore present in all species of the subgenus Zezea is also found among Amara s. str. and Celia , etc. Later, Hieke returned to his idea and expressed it more clearly, proposing to broaden the interpretation of synapomorphism as the ability (potency) of a certain characteristic to emerge: “… eine Synapomorphie nicht der gemeinsame Besitz von apomorphen Merkmalen ist, sondern die gemeinsame genetische Potenz, ein bestimmtes apomorphes Merkmal auszubilden.” ( Hieke 2005: 149). One may disagree with that statement, but it is obvious that the genus Amara shows a very wide combinatorial set of diagnostic characters. A natural reflection of the distribution of features can be presented in a matrix ( Table 1 ). This allows for a comparison between Tibetamara subgen. n. and all other subgenera of Amara .

Bradytus , which previously included A. validula , differs from Tibetamara subgen. n. in having a groove on the right side of the median lobe of aedeagus, margination on the prosternal intercoxal process, presence of a punctate area or a deep fossa in the middle of the male prothorax, fewer (1–3, rarely 4) setae on the dorsal side of the fore tibia, and a different structure of the tarsi.

The subgenus Bradytulus Tschitschérine, 1894 , is similar to Tibetamara subgen. n. in many characters, but in Bradytulus the proternal intercoxal process margined at least at the apex.

The subgenus Pseudocelia Lutshnik, 1935 differs from Tibetamara subgen. n. in having poorly developed or reduced outer basal foveae of the pronotum. Both Reductocelia Lafer, 1989 and Xenocelia Hieke, 2001 have sclerotized structures in the endophallus, usually 2–3 preapical setiferous punctures at the apex of elytral stria 7, and (in some Reductocelia , in all Xenocelia ) 4 setae on the anal sternite in both sexes. In addition, in Xenocelia , the outer basal foveae of the pronotum are not separated from the lateral margin by a convex fold; males show a punctate area or a fovea in the middle of the prosternum, as well as a short groove on the right side of the median lobe of aedeagus.

Several subgeneric complexes differ from Tibetamara subgen. n. in having either a margined prosternal intercoxal process with additional setae ( Camptocelia Jeannel, 1942 , Xanthamara Bedel, 1899 , Leuris Lutshnik, 1927 , Cumeres Andrewes, 1924 , Heterodema Tschitschérine, 1894 , Leiocnemis C. Zimmermann, 1832 , Paracelia Bedel, 1899 , Pseudoleiromorpha Hieke, 1981 , Percosia C. Zimmermann, 1832 , Phaenotrichus Tschitschérine, 1898 , Neopercosia Hieke, 1978 , Parapercosia Tschitschérine, 1899 , Pseudoleirides Kryzhanovskij, 1968 , Polysitamara Kryzhanovskij, 1968 , and Harpalodema Reitter, 1888 ) or additional setae on the prosternal process are combined with the absence of its margination ( Bradytodema Hieke, 1983 , some Pseudoleirides Kryzhanovskij, 1968 and Pseudoleiromorpha Hieke, 1981 ).

Finally, a number of subgenera with an unmargined prosternal intercoxal process, as in Tibetamara subgen. n., possess numerous additional setae on the femora of the middle and hind legs ( Phanerodonta Tschitschérine, 1894 , Hyalamara Tschitschérine, 1903 , Ammoxena Tschitschérine, 1894 , Cribramara Kryzhanovskij, 1964 , Amathitis C. Zimmermann, 1832 , Allobradytus Iablokoff-Khnzorian, 1975 , Ammoleirus Tschitschérine, 1899 , and Zabroscelis Putzeys, 1866 ).

Often, the development of additional setae on the legs and ventral surface, apparently associated with a psammophilic lifestyle, is also accompanied by the complication of tarsal setae. In certain cases, apical groups of long setae are formed ( Harpalodema Reitter, 1888 , Phanerodonta Tschitschérine, 1894 , some species of Amathitis C. Zimmermann, 1832 ), resembling the tarsi of Tibetamara subgen. n. in appearance. However, in all these other subgenera, it is not the number, but the length of the tarsal setae that is increased, and they remain arranged in regular lateral rows typical of the genus. An increased number of setae on the tarsi is described for A. (Bradytus) pingshiangi Jedlička, 1957 ( Kavanaugh et al. 2014); however, as this species has an unmargined prosternal intercoxal process and a fovea in the middle of the male prosternum is absent, its inclusion into the subgenus Bradytus is dubious ( Hieke 1990).

Therefore, the subgenus Tibetamara subgen. n. possesses a predominantly plesiomorphic (according to Hieke, 1978, 1983, 2005) set of characters and, in their combination, it is similar to the “ Curtonotus -Komplex” sensu Hieke (1978). It seems noteworthy that Tschitschérine (1898: 217) already noted the similarity between A. validula and Curtonotus Stephens, 1827 , when describing the former. The subgenera of this complex differ from Tibetamara subgen. n. by the presence of large tubercles or teeth on the middle tibia of males, as well as of two lateral rows of short spinules on the ventral surface of the tarsus. Their right paramere is long, with a narrow tip ( Curtonotus, Armatoleirides Tanaka, 1957 ) or with a hook ( Leirides Putzeys, 1866 , Microleirus Kryzhanovskij, 1974 , Leiramara Hieke, 1988 , and Leironotus Ganglbauer, 1891 ). In addition, unlike Tibetamara subgen. n., species of Leirides, Microleirus, and Leiramara have a marginated prosternal intercoxal process, and the male prosternum of Armatoleirides has a punctate fovea in the middle.

As a result, we consider the structure of the aedeagus, primarily a very short right paramere with a blunt tip (Fig. 9), as well as the chaetotaxy of the tarsi, to be the unique features (autapomorphies) among Amara that warrant the recognition of a new subgenus, based on A. validula alone.

Etymology. The name is derived from combining the name of the mountainous plateau Tibet, whence A. validula is reliably known, with the generic name Amara . Feminine.