A review of North and Central American Paragrilus Saunders, 1871 (Coleoptera: Buprestidae: Agrilinae)
Author
Hespenheide, Henry A.
text
Zootaxa
2002
43
1
28
journal article
51453
10.5281/zenodo.155677
4b5b7ab7-b711-433a-a318-49da5604bfc0
11755326
155677
Paragrilus
Saunders, 1871
Paragrilus
Saunders, 1871
: 127
(replacement name for
Clinocera
Deyrolle
).
Type
species:
Agrilus modicus
Solier, 1833
(subsequent designation:
Nelson 1987
: 71
).
Clinocera
Deyrolle 1864
, 116. (name preoccupied, Meigen 1803,
Diptera
).
Type
species: unavailable (no
type
species designation)
Rhaeboscelis
auct. not Chevrolat, 1837.
The genus has been most recently treated by
Cobos (1976)
in relation to the other genera in the subtribe
Rhaeboscelidina
,
Rhaeboscelis
Chevrolat and
Ve
lu t ia Kerremans. Examination of the
type
of
Ve l u t i a sericea
Kerremans shows that genus to be doubtfully distinct from
Paragrilus
.
Characters: Overall, members of the genus are relatively elongate and subcylindrical in form, similar to the genus
Agrilus
, although members of the
P. aeraticollis
and
P. trifoveolatus
groups are more or less flattened dorsally. Colors are typically dark and matte or only weakly shining. Most species are glabrous or inconspicuously setose, although members of the
P. aeraticollis
group are sexually dimorphic in that males possess areas of conspicuous setae on the front.
The front of the head is typically very convex in dorsal view, usually impressed along the midline, especially deeply so in the
P. trifoveolatus
group, one of whose members also possesses a round fovea at the base of the depression. The epistoma is typically depressed and relatively narrow between the antennal insertions, but is broader in the
P. trifoveolatus
group. The ventral margin of the episotoma is produced in some species and is emarginate with more or less sharply acute lateral angles.
The shape and sculpture of the pronotum are the most distinctive features of the species treated here, both in characterizing species groups and in separating species. The genus itself is defined by anterior depressions between the marginal and submarginal carinae which receive the antennae. The posterior angles are usually more or less swollen as a prehumeral callosity and separated from the rest of the pronotal disc by a depression of differing shapes and intensities. In the
P. trifoveolatus
and
P. aeraticollis
groups the prehumeral callosity is produced outward and anteriorly to form a ridge above and roughly parallel to the marginal carina. In the
P. trifoveolatus
group the disc is relatively flattened and has three relatively equal depressions along base which produce an undulating posterior margin. The lateral depressions are relatively weak in the
P. rugatulus
group and stronger and continuing obliquely to the lateral margins in the
P. aeraticollis
group.
The elytra are characterized by a strong posthumeral carina which typically extends to just beyond the posterior coxae, but is longer in a few species. This character is shared with a few species of
Agrilus
(the
A. dissimilis
group; see below). The elytra are usually more or less transversely rugose and relatively unmodified otherwise, except for a subapical raised callosity in a few species. The apices are usually broadly rounded or subtruncate and slightly emarginate.
The ventral surface is relatively unmodified except for the posterior process of the prosternum and form of the hind coxae. The first ventral abdominal segment is produced anteriorly between the hind coxae and usually has carinae on the lateral margins of the process which border depressions for the hind tarsi when the legs are pulled in to the body. Male genitalia are usually distinctive.
The North and Central American species of the genus can be separated into three groups
P. rugatulus
group (
P. exiguus
(Chevrolat)
,
P. lesueuri
Waterhouse
,
P. modicus
(Solier)
,
P. rugatulus
Thomson
,
P. transitorius
Waterhouse
,
P. vicinus
Waterhouse
) somewhat varied, but generally more cylindrical and characterized by a convex, rugose pronotum with weak prehumeral callosities; known plant hosts of adults are in the genus
Sida
(Malvaceae)
.
P. trifoveolatus
group (
P. angulaticollis
Waterhouse
,
P. impressus
(Chevrolat)
,
P. laevicollis
Waterhouse
,
P. tenuis
(LeConte)
,
P. trifoveolatus
Waterhouse
,
P. fallorum
n. sp.
,
P. azureus
n. sp.
) usually more flattened above and characterized by having the pronotum often smoother and with three depressions along base which produce an undulating posterior margin.
P. aeraticollis
group (
P. aeraticollis
Waterhouse
,
P. heliocarpi
n. sp.
,
P. akersorum
n. sp.
,
P. moldenkei
n. sp.
,
P. burkei
n. sp.
) usually more flattened above, the pronotum smooth or rugose, and characterized by males with areas of setae on the front of the head.
Not surprisingly, the species of the
P. rugatulus
group that are associated with the weedy plant genus
Sida
L. in the
Malvaceae
are very common in collections and all described, often multiply. The most poorly known species are members of the
P. aeraticollis
group, in which 4 of the 5 species are previously undescribed. Known adult hosts in this group are all lianas (
Byttneria
Steud.
) or shrubby perennials (
Heliocarpus
L.,
Wissadula
Medik.
) found in forest gaps or edges, but not usually in more open second growth. Many are widely distributed, but three of the species in the
P. trifoveolatus
group apparently have very localized, possibly relictual distributions.