Parygrus parallelus ( Grouvelle, 1890 )

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 : 110-111

Parygrus parallelus ( Grouvelle, 1890)

(Figs 2, 11)

Holotype specimen. BRAZIL: “Theresopolis (Brésil)” ( Grouvelle 1890, p. 146); “Theresopolis (Rio de Janeiro). Collection Grouvelle.” ( Grouvelle 1896a, p. 216). Depository, MNHN. The type was not examined; locality data is from the original and subsequent descriptions. The type could not be located at the MNHN and its current whereabouts is unknown.

Additional specimens, photographic images (2). BRAZIL: “Bresil / Theresop[olis] // Parygrus / parallelus / Grouv. [handwritten]”. Depository, MNHN. Only photographic images and label data from the photos were examined.

Additional specimens examined (8). BRAZIL: “Brasil / Theres[opolis] // Parygrus / parallelus / Grouv. [handwritten]// Coll. Van de Poll / 1937-744. // H.E. Hinton / collection. / B.M. 1977-566. [printed]” (1 specimen; head, pronotum and abdomen missing); “Fry / Rio Jan °. [handwritten] // G. Lewis Coll. / 1915-38. [printed]” (1 specimen); “Beske // Fry / Rio Jan °. [handwritten] // Fry Coll. / 1905-100. [printed]” (1 specimen); “5797 // Beske // Fry / Rio Jan °. [handwritten] // Fry Coll. / 1905-100. [printed] // Parygrus / parallelus / Grouv. [handwritten]” (1 specimen; abdomen missing); “Weir // San / Paulo [handwritten] // Fry Coll. / 1905-100. [printed]” (1 specimen); “27079 // Weir // San / Paulo [handwritten] // Fry Coll. / 1905-100. [printed] // Parygrus / parallelus / [illegible word] Grouv [handwritten]” (1 specimen; head and pronotum missing); “San / Paulo [handwritten] // G. Lewis Coll. / 1915-38 [printed]” (2 specimens; 1 abdomen missing). Depository, NHMUK .

Provisional diagnosis. The type specimen of P. parallelus is much longer (7–8 mm) than the length of the other species except for that of P. angustatus . Considering that an image of the type P. parallelus was not available for examination, the following was observed from images of two non-types (Additional specimens, photographic images) ( Fig. 11 ) in comparison with the type image of P. angustatus ( Fig. 8 ): elytra sinuate laterally, margin explanate at basal third (vs. parallel-sided, not explanate); pronotum widest at base, lateral margins raised and widely explanate (vs. not raised nor explanate), without a median longitudinal carina (vs. with a carina); elytral striae and punctures distinct (vs. striae not distinct, effaced at posterior third, punctures small).

General description. Since we were unable to examine or view an image of the holotype, only a limited description is possible based on the original descriptions ( Grouvelle 1890) and images of other specimens of P. parallelus from the Grouvelle Collection that we assume are correctly identified. From a translation of the original Latin and French descriptions: 7–8 mm long; elongate parallel; weakly convex; transverse carina between antennal insertions; scutellum pentagonal; pronotal anterior margin emarginate, lateral margins widely explanate and raised, fringed with long hairs; elytra not wider than pronotum, punctate-striate. To this we add that the elytral lateral margin is explanate at the basal third, that contrary to the description the elytra appear a little wider than the pronotum, and that it is not possible to see the transverse carina between the antennal insertions ( Fig. 11 ). The latter character is perhaps generic because the frons and clypeus are set at different angles forming a rounded ridge between.

Distribution. Brazil, described from Rio de Janeiro (Fig. 2).

Etymology. Grouvelle did not cite an etymology, but the specific epithet probably refers to the parallel-sided body.

Comments. Grouvelle (1890) originally described P. parallelus in Parnus and subsequently moved it to Parygrus ( Grouvelle 1896a) . The original description in Latin is brief and was presented at a meeting of the Entomological Society of France. The later description includes the verbatim original in Latin, as well as a more detailed one in French.

The holotype could not be located in the MNHN. We were sent images of two specimens of P. parallelus (Additional specimens, photographic images), one of which is included here ( Fig. 11 ), and one image of a series of specimens in a museum unit tray. Several of the specimens in the image bear locality label data which match that of the type locality. At least two pins (one pin bears multiple specimens) have determination labels with the same handwriting as the holotype of P. angustatus and possibly P. elateroides , but the labels do not bear the notation “ty.” in the lower left corner. If the type remains missing, a lectotype should be designated.

We were loaned a series of specimens from the NHMUK (Additional specimens examined), four of which were from the Fry Collection. Three of these bear determination labels with the same handwriting as the specimens labeled as P. parallelus from the Grouvelle collection. Unfortunately, two of them are missing the pronotum (and head), where important diagnostic characters are located. The remaining determined specimen and another Fry specimen, both from Rio de Janeiro, closely resemble those in the MNHN images, as do two other specimens from Sao Paulo collected by Lewis.

Figures

FIGURES 8–11. Parygrus species: 8) Parygrus angustatus, holotype: dorsal habitus; specimen labels; 9) Parygrus angustatus, false holotype: dorsal habitus; specimen labels; 10) Parygrus elateroides, holotype: dorsal habitus; specimen labels; 11) Parygrus parallelus, non-type: dorsal habitus; specimen labels (images 8, 10, 11 provided by the MNHN collection-Paris).