Pericalina (Pericalus), Macleay, 1825

Shi, Hongliang & Liang, Hongbin, 2018, Revision of genus Pericalus from China, with descriptions of four new species (Carabidae, Lebiini, Pericalina), ZooKeys 758, pp. 19-54 : 21-25

Subgenus Pericalus (s. str.) Macleay, 1825

Macleay 1825: 15. Type species: Pericalus cicindeloides Macleay, 1825, by monotypy.

Diagnosis.

The genus Pericalus is distinguished from other genera of Pericalina by the combination of the following characters: dorsal surface glabrous, except for the eighth and ninth elytral intervals which are generally sparsely and very finely setose; black or metallic in color, elytra either unicoloros or with two groups of yellowish patches; eyes strongly prominent; labrum elongate, apex deeply notched; clypeus with apical margin straight; terminal labial palpomere fusiform in both sexes; labial palpifer with one long seta; mentum without median tooth; paraglossa membranous, longer than ligula; third interval of elytra with two to four setigerous pores, the first one near base, the last one very close to apex; fourth tarsomere simple; claws smooth.

The subgenus Pericalus is different from the subgenus Coeloprosopus Chaudoir by its body size being usually larger; in having the lateral channel of the pronotum widely explanate, with the lateral bead indistinct; and the pronotum subequal to the width of head across eyes.

Distribution.

The subgenus Pericalus containing 19 taxa has an Asia mainland-Sundaland distribution pattern. More than half of them (eleven taxa) are distributed through the Asian continent tropical-subtropical areas, and the most diverse region is located in northern Myanmar, northeast India, southeast Xizang, and west Yunnan. The remaining eight taxa are distributed in the Sundaland region (Greater Sunda Islands and Malay Peninsula). There are no species endemic to the Philippines or islands in the Wallacea region, but one species is widely distributed in each region, P. cicindeloides in the Philippines, and P. baehri in Sulawesi.

Habitat.

Many adults of the subgenus Pericalus were collected in daytime under barks of fallen logs in tropical or subtropical forests. Some others were collected during night, fast running on surfaces of dead logs, or occasionally attracted by lights. Species in this subgenus usually have a rather flat habitus, adapting for living under tree bark.

Taxonomic characters.

The most important taxonomic characters in this subgenus are: (1) dorsal coloration, including elytral pattern; (2) number of setigerous pores on the third interval; (3) shape of elytral outer apical angles; and (4) shape of elytral sutural apical angles.

The supposed ground plan for the subgenus is supposed to include two groups of yellowish patches on the elytron (unicolorous in four species); body very flat (but convex in P. gibbosus ); elytra with microsculpture consisting of distinct, very transverse meshes (but nearly isodiametric in P. dux and P. elegans ); outer apical angles of elytra distinct, acuminate to rounded; elytral sutural angles sharp or blunt; third interval of the elytra with three setigerous pores (but four pores in four species, usually two in P. o. formosanus ).

The shape of outer apical angles of elytra can be classified into the following four basal forms: acuminate, apex forming a very sharp angle, strongly projecting, less than 90 degrees (Fig. 21), present in seven species; acute, apex forming a sharp and distinct angle, not or weakly projecting, more than 90 degrees (Figs 22, 24), in two species; obtuse, apex forming an indistinct angle, more than 90 degrees (Figs 23, 25), in five species; rounded, apex fully rounded, not angulate (Figs 26-32), in seven species. There are some taxa, such as P. o. formosanus , with one form of outer apical angle in general (obtuse), but very rarely other forms can be present in a few individuals (rounded or acute).

Most taxa (15 of 19) of the subgenus have two, the anterior and posterior, groups of yellowish patches on elytra; variation includes four and two pattern forms respectively. For different species or individuals belonging to same pattern form, pale markings on certain intervals may be obsolete or their positions moved.

There are four basic forms for anterior patches: round, in six taxa. Usually a single large round or nearly round spot (Figs 1-3, 7-11) occupies some of the third to eighth intervals, two to five intervals in width. In some individuals of P. ornatus (Fig. 12), the spot is somewhat transverse and irregular, similar to the zigzag form, but generally less transverse and with less displacement of odd and even pale markings. Zigzag, in five species. A transverse serrated band occupies the third to seventh intervals (Figs 6, 13-15), with pale markings on odd intervals anteriorly placed and those of even intervals posteriorly placed. Sometimes pale markings on the third and/or seventh intervals are obsolete. In P. baehri pale markings on the third interval are placed much more anteriorly to those on the remainder of the odd intervals. Separated, in two species. The basic pattern includs five small separated spots, only one interval in width for each, placed on the third to seventh intervals respectively. Sometimes spots on the sixth and seventh intervals are obsolete. Longitudinal positions for all spots are similar to those of the zigzag pattern. Double, a special pattern only for P. cordicollis . The double pattern form is composed of two adjacent large spots: the inner one is in the third and fourth intervals, posteriorly placed; the outer one is in the fifth to eighth intervals, anteriorly placed.

Two basic forms exist for posterior patches: separated, in eleven taxa. The basic pattern is composed of three separate spots (Figs 7-12): the first one is in the second and third intervals, posteriorly placed; the pale marking on the second interval is occasionally obsolete. The second one is in the fourth to sixth intervals, anteriorly placed; the pale marking on the fourth interval is occasionally obsolete; the pale marking on the sixth interval is adjacent to that on the fifth ( P. cordicollis , and some P. ornatus and P. acutidens , Figs 7, 11, 12), placed much anteriorly to that on the fifth and forming a small separate spot ( P. amplus , P. obtusipennis , P. obscuratus , Figs 6, 13-15), or obsolete (the remaining four species and most P. ornatus and P. acutidens , Figs 8-10). The third one is in the seventh and eighth intervals, posteriorly placed, sometimes a little before the first spot; the pale marking on the eighth interval is usually obsolete, but present in P. cordicollis , and some individuals of some other species. Single, in three species. The basic pattern is a single large round spot in some of the second to seventh intervals, two to four intervals in width (Figs 1-3). In a few individuals of P. longicollis , the pale marking on the third interval is present and placed posteriorly to the main spot, but is obsolete in most individuals.

Key to the world species of the subgenus Pericalus

Pericalus aeneipennis Louwerens and P. distinctus Dupuis are not included in the key. Detailed discussions on these two very little known and dubious species are provided under remarks of their similar species ( P. elegans and P. obtusipennis ).