Enochrus (Hugoscottia) plicatus, Short, A. E. Z., 2005

Short, A. E. Z., 2005, Two new species of Enochrus Thomson, subgenus Hugoscottia Knisch, from Costa Rica and Mexico (Coleoptera: Hydrophilidae), Zootaxa 865, pp. 1-7 : 2-4

Enochrus (Hugoscottia) plicatus n. sp.

Fig. 1

Type Material. Holotype (Male): “Pine forest 7 mi S., Mazamitla, Jalisco, MEXICO. 1­ XII­48 ”/ “H. B. Leech, Collection”/ “ HOLOTYPE, Enochrus (H.), plicatus, A. E. Z. Short. ” ( USNM).

Type Locality. Mazamitla, Jalisco State, Mexico.

Diagnosis. Segments 2 and 3 of maxillary palpi bulbous and grooved; the punctation on pronotum and elytra relatively fine, the distinctly 4­ridged mesosternal process, the hooked and acutely pointed parameres and non­emarginate anterior margin of the clypeus serve to distinguish this species from other species of Hugoscottia .

Description. Total length 3.6 mm. Color. Elytra and pronotum yellow to light brown, however this specimen is slightly teneral. Maxillary palpi uniformly yellow. Clypeus darkened on central two­thirds. The remaining structures are generally pale. Punctation. General punctation of elytra moderately fine and distinct, distance between punctures 1.5– 2.0X the width of a puncture. Head and pronotal punctation slightly deeper and more distinct. Systematic punctures (sensu Hansen 1991) on elytra and pronotum slightly larger and more impressed than surrounding punctation, each puncture usually bearing a fine short seta. Head. Three segmented antennal club with apical segment about 1.5X as long as penultimate segment. Maxillary palpi short, shorter than width of head anterior of the eyes; second segment as long as width of the mentum; segments 3 & 4 subequal in length; segments 2 & 3 bulbous; dorsal surface of segment 2 and ventral surface of segment 3 wide and flat and slightly curved, with the ability to fit against each other when the joint between them is folded. Mentum with moderately coarse, evenly distributed punctation, each puncture about as wide as deep; slightly depressed on anterior margin. Anterior margin of the clypeus entire, without emargination. Thorax. Prosternum with anterior third slightly depressed, with distinct median carina; posterior two­thirds sparsely pubescent and tectiform but not carinate. Mesosternal process consisting of a longitudinal, obtusely triangular crest with lateral carina on each side; the resulting four ridges meeting near the apex of the process; sides of carinae glabrous and with fine granular microsculpture. Mesosternum with elongate­oval glabrous area posteromedianly; glabrous area slightly more than half the total length of mesosternum. Hind femora pubescent on basal fourfifths. Elytra with a sutural stria in posterior two­thirds to three­fourths. Abdomen. Ventrites uniformly and densely pubescent. Fifth ventrite with shallow posteromedian emargination, distinctly wider than deep and lined with coarse yellow setae. Aedeagus ( Fig. 1 ). Parameres slightly sinuate along outer margin, strongly sinuate along interior margin, with tips curved hooked inward, with an acute apex. Tip of median lobe not reaching apex of parameres; faintly bifid on dorsal side. Basal piece damaged but appearing constricted basally.

Distribution. Jalisco State, Mexico.

Etymology. Derived from the Latin plicatus , after the folding modifications of the maxillary palpi. Used here as a noun in apposition.

Remarks. Other species of Enochrus (e.g. E. (Methydrus) punctipalpus ) are known to have sexually dimorphic maxillary palpi in which only those of the male are modified. As only a single male is known of E. plicatus , it not yet known if this is true in this case.

In his unpublished Ph.D. thesis, Gundersen (1967) records Enochrus (Enochrus) oviformis d’Orchymont , a Brazilian species, from Mexico. One of the four specimens he examined has the exact label data as the holotype of E. (H.) plicatus , and Gundersen’s illustration of the aedeagus and maxillary palpus leave little doubt that it is the same specimen, although it bears no label to demonstrate such a fact. There is no mention by Gundersen of the distinct mesosternal process that would unambiguously place this species in Hugoscottia . I here treat Gundersen’s (1967) Mexican records of E. oviformus as a misidentification of E. (H.) plicatu s. Gundersen’s subsequent 1977 and 1978 publications do not treat E. oviformis . The localities for the other specimens of ‘ E. oviformis ’ in Gundersen’s thesis are “ 15–20 mi. W. Jiquilpan” in Jalisco State and “Rio Metloc, nr. El Fortin” in Veracruz State. I have not been able to locate or verify these other specimens are conspecific with E. (H.) plicatus , in part because no list of depositories was provided; they do not appear to be in the USNM collection.

Figures

FIGURES 1 & 2. Aedeagi, dorsal views. – 1, Enochrus (Hugoscottia) plicatus (holotype). 2, Enochrus (Hugoscotia) talamanca (holotype).