Maladera setifera ( Gyllenhal, 1817 ), 2019

Ahrens, Dirk, Fabrizi, Silvia, Nikolaev, Katharina, Knechtges, Lisa & Eberle, Jonas, 2019, On the identity of some taxa of Sericinae described by C. P. Thunberg and L. Gyllenhal (Coleoptera, Scarabaeidae), Bonn zoological Bulletin 68 (1), pp. 21-29 : 22-24

Maladera setifera ( Gyllenhal, 1817) comb. n.

( Fig. 1A–F )

Melolontha setifera Gyllenhal, 1817: 95 ; Wallin 1994: 9.

Serica setifera : Brenske 1898: 218; Dalla Torre 1912: 15; Krajcik 2012: 243; Ahrens & Fabrizi 2016: 273.

Type material examined. Lectotype (here designated). ♂ “ Uppsala Univ. Zool. Mus. Gyllenhal saml. Typ nr. 1467/ c” ( UUZM) . Paralectotypes: 1 ♀ “ Uppsala Univ. Zool. Mus. Gyllenhal saml. Typ nr. 1467/ b” ( UUZM) , 1 ♀ “ Uppsala Univ. Zool. Mus. Gyllenhal saml. Typ nr. 1467/ a” ( UUZM) .

Additional material examined. 1 ♂, 3 ♀♀ “ Indonesia C. Java Mt. Sumbing, VI.2006 St. Jakl leg.” ( ZFMK) , 1 ♂ “ Indonesia W. Java Puncak near Boggor , 1500m, 8.–10.IV.1992, Eddi Samin leg.” ( ZFMK) .

Lectotype redescription. Length: 7.3 mm, length of elytra: 5.8 mm, width: 4.9 mm. Body oblong-oval, yellowish brown, antenna yellowish, dull, labroclypeus shiny, with a few robust setae on head, otherwise glabrous.

Labroclypeus short, wide and subrectangular, widest at base, lateral margins slightly convex, slightly convergent anteriorly, anterior angles strongly rounded, anterior margin straight, margins strongly reflexed; lateral margin and ocular canthus produce an indistinct angle; surface convexly elevated medially, finely, densely punctate, with a few erect, long setae; frontoclypeal suture distinctly incised and elevated, angled medially; smooth area anterior to eye convex, twice as wide as long; ocular canthus short and narrow (1/3 of ocular diameter), finely densely punctate, with a terminal seta. Frons dull, with moderately dense, coarse punctures, with a few single setae beside eyes and behind frontoclypeal suture. Eyes moderately large, ratio diameter/ interocular width: 0.62. Antenna with ten antennomeres; club with three antennomeres and straight, slightly longer than remaining antennomeres combined. Mentum elevated and slightly flattened anteriorly.

Pronotum moderately transverse, widest at middle, lateral margins moderately evenly convex and convergent anteriorly as well as posteriorly, anterior angles distinctly produced and sharp, posterior angles blunt, slightly rounded at tip; anterior margin straight, with fine marginal line, base without marginal line; surface moderately densely and finely punctate, with minute setae in punctures; anterior and lateral margin finely sparsely setose; hypomeron carinate, not produced ventrally. Scutellum wide, triangular, with fine, moderately dense punctures, impunctate on midline.

Elytra widest at middle, striae finely impressed, finely and densely punctate, intervals slightly convex, with fine, moderately dense punctures concentrated along striae and with minute setae in punctures, odd intervals (most abraded) with a few single long setae in robust punctures; epipleural edge fine, ending at anterior third of elytra, epipleura sparsely setose; apical border of elytra membraneous, with a fine rim of microtrichomes (visible at ca 100x magnification).

Ventral surface dull, finely and densely punctate, nearly glabrous, metasternal disc sparsely covered with fine, short setae; metacoxa with a few longer setae laterally. Abdominal sternites finely and densely punctate, punctures with minute setae, each sternite with a transverse row of punctures each bearing a fine seta. Mesosternum between mesocoxae as wide as mesofemur. Ratio of length of metepisternum/metacoxa: 1/1.95. Pygidium moderately convex, dull, finely and densely punctate, with narrow smooth midline, with numerous long setae along apical margin.

Legs short and wide, dull; femora with two longitudinal rows of setae, finely and sparsely punctate. Anterior margin of metafemur acute, without adjacent serrated line, anterior row of setae complete; posterior ventral margin smooth, moderately widened at ventral apex, dorsal posterior edge smooth, neither serrate, glabrous. Metatibia short and wide, widest at middle, ratio of width/length: 1/2.25, sharply carinate dorsally, with two groups of spines, basal group shortly behind middle, apical group at three quarters of metatibial length, in basal half with a few short single setae subparallel to dorsal margin; lateral face longitudinally convex, superficially and sparsely punctate, along midline broadly smooth, with minute setae in punctures; ventral margin finely serrate, with five equidistant robust setae; medial face smooth and glabrous; apex finely serrate, shallowly sinuate interiorly near tarsal articulation. Tarsomeres dorsally impunctate, glabrous, neither laterally nor dorsally carinate, moderately setose ventrally; metatarsomeres with a strongly serrated ridge ventrally and a smooth subventral longitudinal carina, glabrous; first metatarsomere slightly shorter than following two tarsomeres combined and slightly longer than dorsal tibial spur. Protibia moderately long, bidentate; anterior claws symmetrical, basal tooth of both claws bluntly truncate at apex.

Remarks. The designated lectotype is the only male specimen of the syntype series. The paralectotypes nr. 1467a and 1467b belong to clearly different species, however, their identity remains unclear because they are female. Type nr. 1467a somewhat resembles Maladera subspinosa ( Brenske, 1898) from northeastern India, while type nr. 1467b is very similar to Maladera holosericea (Scopoli, 1772) , which definitively would not occur at the presumptive type locality in Asia. Originally, there were syntypes in the Schönherr collection too, however, none was presently found in the Stockholm Museum of Natural History.

In contrast to that, the original description mentions only two variants, one corresponding to the lectotype (var. b), and the other one to type nr. 1467a (nominal form). None of the characters of the latter contain species specific traits that are useful without the exact geographic provenience of the specimens, and, it cannot be excluded that the specimens of the type series have been collected in two completely different areas, as also the potential presence of M. holosericea in the labelled syntypes series suggests.

For long time it was believed that the species originated from India ( Brenske 1898; Dalla Torre 1912) because the type locality was originally given as India orientalis (“habitat in India orientali”; Gyllenhal 1817). Since the designed lectotype fits to 100% recently collected and geographically well-defined material, the type locality could be more strictly circumscribed to Java. Indeed, the most important ports on the East India route were Cape, Batavia and Canton, and thus the two latter are the completely dominant places of origin for specimens labelled “ India orientalis” in Swedish collections, and supporting the identification of the type locality as being Java (Mattias Forschage, pers. com.). This is further supported by geographically rather restricted distributions of species of the M. thomsoni species group, which includes M. setifera .

Figures

Fig. 1. A–F. Maladera setifera (Gyllenhal, 1817) (lectotype); G–J. Microserica pusilla (Thunberg, 1818) (lectotype); K–N. Ablaberoides fuliginosus (Thunberg, 1818) (lectotype). A. Aedeagus, left side lateral view; D. Aedeagus, right side lateral view; B. Parameres, dorsal view; C. Parameres, ventral view; G, K. Head, dorsal view; E, J, M. Habitus, dorsal view, I, N. Habitus, lateral view; F, H, L. Specimen labels. Scale: 0.5 mm.