Crenulister dentatus, Caterino, Michael S. & Tishechkin, Alexey K., 2014

Caterino, Michael S. & Tishechkin, Alexey K., 2014, New genera and species of Neotropical Exosternini (Coleoptera, Histeridae), ZooKeys 381, pp. 11-78 : 61-63

Crenulister dentatus sp. n. Figs 23 C–D, 25 H–J, Map 5

Type locality.

GUYANA: Potaro-Siparuni (Region 8), Iwokrama Forest [4.2844°N, 58.5097°W].

Type material.

Holotype male: "GUYANA: Region 8, Iwokrama Forest, Kabocalli Field Stn., 60m, 4°17'4"N, 58°30'35"W, 3-5 JUN 2001 R. Brooks,Z.Falin GUY1BF01 146 ex: flight intercept trap" / "SM0573091 KUNHM-ENT [barcode label]" (SEMC).

Other material.

1: BRAZIL:Mato Grosso: Cotriguaçu, Fazenda São Nicolau, Prainha, 9°51.6'S, 58°12.9'W, x.2009 (CEMT); 1: PERU:Loreto: Campamento San Jacinto, 2°18'44.85"S, 75°51'46"W, 175-215m, 3-12.vii.1993, R. Leschen, FIT (SEMC).

Diagnostic description.

Length: 1.9-2.0 mm, width: 1.6-1.8 mm; as for generic description with the following diagnostic characters: body rufescent, elongate ovoid, subdepressed; frontal stria well impressed, complete, frontal disk moderately depressed, with few rather conspicuous secondary punctures against fine background punctation; epistoma with lateral ridges delimiting median depression bearing very weak fragments of lateral striae; labrum about 4 × wider than long, apical margin weakly emarginate; pronotum with single median gland opening about one-third from anterior margin; pronotal sides with weakly crenulate, slightly raised lateral submarginal stria; secondary punctures of pronotal disk small, sparse, slightly larger and denser in basal half; weak prescutellar impression present; elytron with single complete crenulate epipleural stria; all dorsal striae complete, coarsely impressed; elytral interstriae irregularly, sparsely punctate, inner intervals with 8-10 punctures, fewer in outer intervals; prosternal keel deeply emarginate at base, with carinal striae slightly abbreviated, separate anteriorly; prosternal lobe deflexed, marginal stria present only at middle; mesoventrite with marginal stria weakly crenulate, mesometaventral stria crenulate, subangulate to near mesoventral midpoint; postmesocoxal stria recurved anterad around mesocoxa, reaching mesepimeron; lateral metaventral stria rather weakly crenulate, extending nearly to middle of metacoxa; metaventral disk with secondary punctures distinctly smaller and sparser anteromedially; metepisternal punctures separate, not coalesced into a stria; lateral stria of 1st abdominal ventrite weakly impressed along inner edge of metacoxa; secondary punctures of median portion of 1st abdominal ventrite smaller and sparser in posterior half, with slightly oblique punctures toward sides behind metacoxa; punctures along posterior margins of ventrites 1-2 transversely elongate but separate, those of ventrites 3-4 intermittently coalesced into marginal strioles; protibia 5-6-spined, with marginal dentation rather well-developed; meso- and metatibia with 4-5 thin, elongate spines, on metatibia mainly along apical half of margin; propygidium with secondary punctures shallow but rather large, uniformly separated by less than half their diameters in basal half, rather discretely obsolete in posterior half; propygidial gland openings present in anterolateral corners but difficult to distinguish from secondary punctures; propygidial strioles absent; pygidium largely lacking secondary punctures; pygidial gland openings not evident; pygidial margin lacking striae. Male (Fig. 25A, H–J): accessory sclerites absent; T8 with ventrolateral apodemes broad, widely separated ventrally; S8 with halves meeting only at basal corner, inner margins short and strongly divergent, apices very narrow, without setae or membranous velum; T9 with apices subacute; T10 deeply, narrowly emarginate at apex; S9 widened to weakly emarginate base, apex narrowly and rather deeply emarginate; tegmen widest just beyond middle, narrowed to apex, apices barely separated, medioventral process produced beneath near midpoint; median lobe about one-third tegmen length, basal piece about half tegmen length.

Remarks.

This species is defined by the relatively well developed protibial marginal teeth (Fig. 23D), with deep emarginations between spine insertions. In addition to this character, the species lacks a marginal pygidial stria and secondary pygidial punctures. Its pronotal gland openings are not multiplied, exhibiting only single openings on each side about one-third the pronotal length from the anterior margin, and the sub-basal pygidial gland openings appear to be absent (this is difficult to ascertain). The three specimens attributed here agree in all these characters. However, they also exhibit considerable differences, with the two specimens excluded from the type series showing finer punctation in general, especially more or less lacking elytral interstrial punctures. The Peruvian individual is further distinguished by a rather distinctly explanate pronotal margin. However, as the type is the only male among them, we tentatively lump them together for the present. This will clearly need to be revisited if and when additional material becomes available.

Etymology.

This species is named for its distinctively dentate protibiae.