Parygrus erichsoni Waterhouse, 1876

Barr, Cheryl B. & Shepard, William D., 2020, Hiding in plain sight: rediscovery and review of Parygrus Erichson, 1847, with description of five new species from the Neotropics (Coleoptera: Byrrhoidea Dryopidae), Zootaxa 4755 (1), pp. 99-128 : 104-107

Parygrus erichsoni Waterhouse, 1876

(Figs 2, 5, 6, 7)

Type material. Holotype female. “Type [circular off-white label with red border, printed] // Colum/bia [ Colombia] 46 /20 [label reverse side] [circular off-white label, handwritten] / Parygrus / Erichsoni, / (Type.) C. Waterh.

[Waterhouse][off-white label, handwritten] // NHMUK 010580154 [white bar code label, printed]” ( Fig. 5 ). Depository NHMUK. In his description, Waterhouse (1876:19) simply stated “Columbia. Brit. Mus.”

Additional specimen examined. Male. COLOMBIA: “Columbia [Colombia] [circular off-white label, handwritten] // NHMUK 010580155 [white bar code label, printed]” (Fig. 6). Depository NHMUK.

Diagnosis. The male genitalia of Parygrus erichsoni (Fig. 7) are distinctive (among species for which the genitalia are known), although like P. maya n. sp. (Fig. 13) they bear a subapical tooth on the inner margins of each paramere. In the latter species, however, the penis does not closely approach the paramere teeth, while in P. erichsoni the penis nearly reaches the teeth. Also, the paramere tips of P. erichsoni are blunt in lateral view, whereas in P. maya n. sp. they are acute. Externally they are also dissimilar as follows: Parygrus erichsoni ( Figs 5 , 6) is covered with setae that are long, dark, coarse, and erect on the dorsum; and the pronotum is much wider at base than apex. Parygrus maya n. sp. ( Fig. 12 ) has setae shorter, yellow, finer, and semi-erect; and the pronotum is usually almost as wide at apex as base. Note that this diagnosis of P. erichsoni is based on only two specimens.

Redescription. Holotype female. Cuticle dark brown, legs, antennae and mouthparts lighter; elongate, subcylindrical; length 5.75 mm (including head), 5.40 mm (excluding head, pronotum + elytra), 2.10 mm wide; body covered with long, erect, and short, fine, recumbent setae; pronotum slightly narrower than elytra ( Fig. 5 ).

Head dark brown; punctation shallow, dense, punctures separated by about 1x puncture diameter; setae moderately long, erect; vertex depressed in middle; frons protruding forward between antennal bases, anterior margin arcuate, distance between antennal bases less than length of antennomere 1. Antenna with antennomeres 1 and 2 red-brown, setose, antennomeres 3–11 yellow-brown, densely setose; antennomere 1 shorter than antennomere 2; antennomere 2 covering antennomeres 3–5. Clypeus barely emarginate, setose, coarsely punctate. Maxillary palpus with terminal palpomere elongate, subcylindrical, weakly curved. Labrum emarginate, coarsely punctate, densely covered with long, erect setae. Labial palpus with terminal palpomere flattened, shorter than terminal maxillary palpomere.

Pronotum dark brown; convex, disc slightly flattened at center; length 1.25 mm, width 2.05 mm, widest at basal 1/4–1/3. Anterior border straight except at strongly acute, depressed, anterolateral angles; lateral margins narrowly margined, weakly arcuate, sinuate at moderately explanate, acute, posterolateral angles; posterior border trisinuate. Disc densely punctate, punctures separated by 1x puncture diameter; setae numerous, erect, moderately long. Scutellum : dark brown; subcordate, wider than long; anterior margin arcuate between two anterolateral notches, lateral borders nearly straight; disc flat, punctate.

Elytron dark brown; length 4.15 mm, width 1.05 mm; widest at posterior 1/3; depressed at base. Disc strongly striate and punctate, with deep, closely spaced, quadrate punctures separated by less than a puncture diameter, distinct to apex; intervals convex. Semi-erect setae moderately long, widely and evenly spaced; recumbent setae short, closely spaced. Hind wing: macropterous.

Legs. Profemur red-brown, covered with fine, evenly spaced punctures and long, recumbent golden setae; protibia weakly arcuate, red-brown, mostly bare and shiny, dorsal surface with sparse, very long setae, ventral surface with dense row of short setae at distal 1/2; protarsus yellow-brown, shiny, dorsal surface with sparse, very long setae, ventral surface with row of short, semi-erect setae, protarsomere 5 with two pairs of longer setae at apex. Mesofemur similar to profemur; mesotibia weakly arcuate, red-brown, ventral setae much longer than those of protibia and more numerous; left mesotarsus similar to protarsus except ventral setae much longer and more numerous [right mesotarsus missing]. Metafemur, metatibia and metatarsus all similar to those of mesoleg.

Venter dark red-brown; heavily setose, evenly punctate. Prostenum long; anterior border narrowly margined; prosternal process wide and slightly depressed between procoxae, parallel-sided with thick margins; process with low, median longitudinal carina terminating in a low, oval protuberance near apex. Mesoventrite very short. Metaventrite about as long as prosternum; intercoxal process margined and flat; posterior disc depressed at junction of sulcate metakatepisternal suture and metathoracic discrimen, discrimen angled posteriorly at junction. Abdomen with long setae more dense than on rest of body; ventrite 1 with triangular intercoxal process margined, slightly depressed between metacoxae; ventrites 2–4 of equal length, evenly punctate, punctures aligned with faint, transverse strigae; ventrite 5 longest, punctate, sparsely granulate laterally, disc centrally depressed, apex with small, angular ventrally directed protuberance, covered with long setae prominent at margins.

Male specimen. Length 5.25 mm (including head), 5.10 mm (excluding head, pronotum + elytra); 1.85 mm wide; somewhat smaller than the female holotype. The protibia of the male (Fig. 6) is weakly deflexed at the apical 1/2 and has a ventral, granulate carina, unlike that of the female ( Fig. 5 ), but otherwise is morphologically similar to the female except for the sexual differences exhibited in abdominal ventrite 5.

FIGURE 6. Parygrus erichsoni , non-type associated male: dorsal habitus; ventral habitus; lateral habitus; frontal view; specimen labels (specimen images provided by the NHMUK).

FIGURE 7. Parygrus erichsoni , male genitalia: a) dorsal view; b) lateral view; c) ventral view.

Genitalia. Aedeagus stout (Fig. 7). Phallobase about 1.5x longer and a little wider than paramere bases together. Parameres each blade-like, inner surface concave, in dorsal view each with an inward-facing tooth just before apex; teeth overlapping, apices capable of contacting each other; in lateral view each paramere wide, ventral surface nearly straight, dorsal surface broadly arcuate, paramere tip blunt. Penis 3/4 or more length of paramere, terminating just before paramere teeth; in dorsal view wider than paramere at midlength; evenly tapered to a slightly produced, blunt apex; dorsum longitudinally carinate. Note: The specimen no longer appears as in Fig. 6. In order to dissect the genitalia, the specimen was removed from the original pin and later remounted on a pinned card point along with abdominal ventrites 3–5; the aedeagus is stored in glycerine in a genitalia vial pinned beneath the specimen.

Geographic distribution. Known only from Colombia. Because the specific type locality is unknown, the star on the distribution map is positioned mid-country (Fig. 2).

Etymology. Waterhouse did not cite an etymology, but the specific epithet undoubtedly honored Dr. W. F. Erichson, the author of the genus and a noted, early German entomologist who specialized in Coleoptera .

Comments. Waterhouse (1876) wrote his description of P. erichsoni in Latin followed by an English comparison with the species Parnus prolifericornis Fabricius, 1792 (synonym of Dryops auriculatus ( Geoffroy, 1785)) . At the end of the Latin description is the line “Long. 2 ¾ lin.; lat. 1 lin.” This is likely the length vs. width body proportions. Waterhouse made no mention of the number of specimens before him. However, the type female and associated male have nearly identical locality labels with the same handwriting and were mounted similarly. Parygrus erichsoni is the type species of the genus.

Figures

FIGURE 5. Parygrus erichsoni, holotype female: dorsal habitus; ventral habitus; lateral habitus; frontal view; specimen labels (specimen images provided by the NHMUK).

FIGURE 12. Parygrus maya n. sp., male; 4.60 mm long, 1.70 mm wide: a) dorsal habitus; b) lateral habitus. FIGURE 13. Parygrus maya n. sp., male genitalia: a) dorsal view; b) lateral view; c) ventral view.