Lacrimorpha, 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 : 37-38

Lacrimorpha gen. n.

Type species.

Lacrimorpha glabra sp. n.

Description.

Size range: Length 1.8-2.2 mm; width 1.5-1.8 mm; Body: body depressed, sublimuloid, with sides rounded and pygidia variably prolonged, generally lightly colored, rufescent to rufo-brunneus, smooth, with fine ground punctation but very little secondary punctation. Head: frons and epistoma convex, prominent, frons rather broad with frontal stria complete, weakly recurved at middle; supraorbital stria fine, usually detached at sides; epistoma weakly emarginate apically; labrum short inwardly arcuate, about 4 × wider than long; mandibles rather short, basal denticles on incisor very small to obsolete; submentum transversely depressed, posterolateral margins raised, apical margin produced slightly into base of oral cavity; mentum about twice as wide as midline length, sides narrowed, apex weakly emarginate; maxillary cardo glabrous, stipes with two setae along lateral margin, basal palpomere short, 2nd and 3rd palopmeres short, subequal, ultimate palpomere narrowed apically, about 1.5 × as long as penultimate; antennal scape weakly expanded to apex, weakly carinate along inner margin, funicle narrow at base, weakly widened to 7th and disc-like 8th antennomere; antennal club tomentose, basal annulus obsolete, middle annulus with slightly basally expanded sensory patch on upper surface, simple on lower surface, apical annulus poorly defined, transverse. Pronotum: pronotal sides arcuate, strongly convergent to anterior corners; prescutellar impression absent; median pronotal gland openings very fine, one pair along anterior margin laterad eye, one pair behind eye about two-thirds pronotal length from anterior margin; marginal pronotal stria complete and continuous along lateral and anterior margins; submarginal stria complete laterally, not extending mediad behind head, very close to marginal stria, intervening disk narrowly convex. Elytra: elytral striation strongly reduced, single epipleural stria present, complete, diverging from margin in anterior half, outer subhumeral stria complete, nearly meeting 1st dorsal stria apically, inner subhumeral stria absent, oblique humeral stria faint, 1st dorsal stria more or less complete, may be slightly abbreviated basally, may be extended mediad along posterior margin of elytron, 2nd and third dorsal striae weakly impressed, present in basal half or less, 4th and 5th striae completely absent, sutural stria usually represented only by extremely short striole at posteromedian corner of elytron, may be extended laterad by apical marginal stria. Prosternum: prosternal keel narrow, acutely emarginate at base, carinal striae weak to absent; prosternal lobe about half as long as keel, marginal stria present or absent. Mesoventrite: mesoventrite acutely produced in front, marginal stria complete, with varied fine strioles in anterolateral corners; mesometaventral stria absent. Metaventrite: mesoventrite with postmesocoxal stria present, varied in length, lateral metaventral stria absent; median portion of metaventral disk with fine ground punctation only, grading to coarser punctures laterad coxae, punctures along metaventral-metepisternal suture may coalesce into stria; metepisternum often with longitudinal stria. Abdomen: 1st abdominal ventrite with single faint to abbreviated stria along inner margin of metacoxa, generally curved laterad behind coxa, disk faintly strigose at sides; ventrites 2-4 with posterior marginal stria along lateral thirds or more; ventrite 5 variously prolonged, apical margin strongly arcuate; propygidium flat or faintly depressed at sides, with basal marginal stria, complete or not; propygidial disk without obvious gland openings; pygidium with apex subacute to very prolonged and acuminate, with lateral marginal striae or not. Legs: all femora flattened and slightly expanded, arcuate on anterior and posterior edges; each trochanter with single seta; protibia with inner and especially outer edges arcuate, narrowing apically, the outer edge bearing 6-7 strong spines, denser near apex, lacking emarginations between, two apical protibial spurs present, strongly reduced, anterior surface of protibia with tarsal groove almost obsolete; protarsus of both sexes bearing spatulate ventral setae; meso- and metatibiae very narrow, parallel-sided, bearing a few thin spines toward apex of inner and outer edges; meso- and metatarsi as long or longer than corresponding tibia, with long, ventral setae that may be vaguely spatulate. Male genitalia: accessory sclerites present, basal; T8 with weakly developed ventrolateral apodemes, apical margin may be slightly desclerotized, basal membrane attachment line intersecting basal emargination; S8 divided, inner edges divergent in apical half, lateral guides weakly to moderately developed, apices narrowed, bearing a few conspicuous setae near apical corners; T9 with ventrolateral apodemes only very weakly developed, not hooked, apices narrowed, acute at inner corners; T10 weakly sclerotized, completely divided; S9 broad, sclerotized along edges, with small apical emargination and weak apical flanges; tegmen flattened, moderately broad basally, slightly narrowed apically, lacking ventromedial process; median lobe more than half as long as tegmen, with proximal apodemes prominent, abruptly narrowed at extreme proximal end; basal piece long, about half as long as tegmen, with prominent apicoventral point. Female genitalia: T8 forming a single plate, apically desclerotized, with shallow, arcuate basal emargination; S8 tripartite, with median sclerite weakly divided from lateral sclerties, basal baculi narrowly attached to lateral sclerites, evenly convergent proximally; S9 weakly sclerotized, elongate, articulated with strap-shaped extension from apex of S8; T10 broad, apically arcuate; valvifers paddle-shaped, paddles nearly one-half total length; coxites elongate, two-thirds length of valvifers, tridentate, with very prominent median tooth dwarfing teeth on either side; gonostyle long, bisetose, inserted between two lateral-most apical teeth; bursa copulatrix membranous, weakly expanded; spermatheca weakly sclerotized, approximately spherical, borne on long thin stalk inserted at base of common oviduct, with elongate, weakly spiraled spermathecal gland attached near its base.

Diagnosis.

This genus is easy to recognize based on its sublimuloid shape (Fig. 16), with the body depressed, the sides rounded, and the pygidium variably prolonged and subacute. Its convex frons is also unusual, as are the rounded, spinose protibiae, the very narrow meso- and metatibiae, the reduced elytral striation, and the almost complete lack of secondary punctation. Lacrimorpha is resolved as the sister group of the genus Mecistostethus in our recent analysis of Exosternini relationships (Caterino and Tishechkin in review).

Etymology.

The name of this genus means 'tear-drop shaped’, resulting from its tapered posterior end. The genus is feminine.

Key to species of Lacrimorpha