Phylogenetic systematics of the genera Plochionocerus Dejean and Agrodes Nordmann (Coleoptera: Staphylinidae: Xantholinini)
Author
Asiain, Julieta
Author
Márquez, Juan
Author
Morrone, Juan J.
text
Zootaxa
2007
1584
1
53
journal article
10.5281/zenodo.178410
ba2b7965-13f3-401f-9c5a-1705938112ea
1175-5326
178410
Agrodes
Nordmann, 1837
stat
. rev.
Agrodes
Nordmann, 1837
: 161
(
type
species:
A
.
elegans
Nordmann, 1837
, by monotypy);
Erichson, 1847
: 88
;
Lacordaire, 1854
: 66
;
Gemminger & Harold, 1868
: 599
(synonym of
Sterculia
);
Sharp, 1876
: 192
;
Bernhauer & Schubert, 1914
: 314
(subgenus of
Sterculia
);
Blackwelder, 1952
: 42
(subgenus of
Plochionocerus
);
Newton, 1995
: 51
(request to the ICZN to place
Agrodes
on the Official List of Generic Names in Zoology); ICZN, 1996: 215 (Official List of Generic Names in Zoology).
Diagnosis.
Body bright metallic; head conspicuously oblong (length/width: 1.54–2.00); lateral margins of the head contiguous dorsally and ventrally, lacking lateroventral furrows; ventral surface of the head with very dense, not expanded, umbilicate punctures (> 30 on each half of the head) distributed homogeneously; anterior margin of labrum with two pairs of small, lateral teeth and a pair of central, longer teeth (
Fig. 37
); mandibles almost as long as half of the head length; apical labial palpomere elongate; upper line of the pronotal hypomeron completely developed (
A. conicicollis
) or absent (
A. elegans
), slightly directed downwards in anterior third, but clearly distinct from lower line; pronotal hypomeron with fine, scarce setae in all area or in posterior 2/3; posterior margin of the elytra lacking notch; and internal margin of the tibiae with brush of dense and light setae covering the basal half or basal 2/3 of the tibiae.
Redescription.
Total length
17.5–23.8 mm
. Body metallic blue, green or violet.
Head
. Elongate (length/width: 1.54–2.00), narrow posteriorly, dorsally with dense, umbilicate punctures (
Fig. 3
), ventral surface with very dense, not expanded, umbilicate punctures (>
30 in
each half of head) distributed homogeneously (
Fig. 67
); lateral margins of head without lateroventral furrows (
Fig. 10
); antennae with basal antennomere longer than antennomeres 2+3 combined, second antennomere shorter than third, remaining antennomeres shorter than second, apical antennomere shorter than antennomeres 9+10 combined (
Figs. 22, 23
); anterior margin of labrum with two pairs of small, lateral teeth and a pair of bigger, central teeth (
Fig. 37
); mandibles acute, almost as long as half of head length, with two teeth on left mandible and one on right, with channel on external basal half (
Figs. 38, 39
); first maxillary palpomere shorter than remaining articles, second longest, third almost as long as apical palpomere and slightly widened toward apex, apical palpomere elongate-conical (
Fig. 42
); first labial palpomere shorter than palpomeres 2+3, second almost as long as apical or slightly longer and slightly widened toward apex, apical palpomere elongate (
Fig. 42
). Neck narrow, with anterior corners obtuse (
Fig. 67
).
FIGURES 69–78.
Ventral (left) and lateral (right) view of aedeagus: 69,
Philonthus testaceipennis
; 70,
Homalolinus flavipennis
; 71,
Thyreocephalus puncticeps
; 72,
Renda fimetaria
; 73,
R. flagellicornis
; 74,
R. leprieuri
; 75,
Agrodes conicicollis
; 76,
A. elegans
; 77,
Plochionocerus ashei
; 78,
P. discedens
. Scale bar 1 mm.
FIGURES 79–87
. Ventral (left) and lateral (right) view of aedeagus: 79,
Plochionocerus fulgens
; 80,
P. h e r m a n i
; 81,
P. humeralis
; 82,
P. ig neu s
; 83,
P. impressipennis
; 84,
P. janthinus
; 85,
P. marquezi
; 86,
P. modestus
; 87,
P. newtonorum
. Scale bar 1 mm.
FIGURES 88–93.
Ventral (left) and lateral (right) view of aedeagus: 88,
Plochionocerus pronotalis
; 89,
P. puncticeps
; 90,
P. reticularis
; 91,
P. simplicicollis
; 92,
P. s p l e n d e n s
; 93,
P. transversalis
. Scale bar 1 mm.
Thorax
. Pronotum smooth; with fine, dispersed setiferous punctures, central longitudinal area without punctures (
Fig. 3
); lateral margins of posterior half slightly sinuate; posterior part of pronotum with slightly visible, depressed area in each half; upper line of pronotal hypomeron completely developed, except in anterior third (
A. conicicollis
,
Fig. 65
) or absent (
A. elegans
,
Fig. 66
), slightly directed downwards in anterior third, but clearly distinct from lower line; pronotal hypomeron with fine, scarce setae on whole area or in posterior 2/3 (
Figs. 65, 66
). Scutellum with scarce punctures. Elytra almost as long as pronotum; with dense, setiferous punctures; posterior margin without notch (
Figs. 3
,
58
). Prosternum slightly oblong (length/width ratio 1.04–1.20;
Fig. 67
), with fine, dispersed setae (
Fig. 67
). Mesoventrite short and wide, surface smooth and with scarce setiferous punctures on posterior margin. Metaventrite biggest, with its surface smooth and with few setiferous punctures.
FIGURE 94
. Strict consensus cladogram. Black circles = synapomorphies; open circles = homoplasies; font numbers refer to clades discussed in the text.
Legs
. Long and slender; femora with dispersed setae on the internal and external faces; internal face of tibiae with brush of dense white setae in the basal half or 2/3 (
Fig. 61
), with apical spines, of which the internal one is longest; first and second tarsomeres almost equal in length, longer than third and fourth, third longer than fourth, and fifth longest (almost as tarsomeres 2+3 combined).
Abdomen
. Surface with smooth and setiferous punctures as dense or slightly less dense than those on elytra; fifth and sixth visible abdominal segments conspicuously narrow than previous segments; male genital sternite elongate, asymmetrical and acute toward apex, with setae in anterior part, wider than genital tergite.
Aedeagus
. Variable in shape (
Figs. 75, 76
).
FIGURE 95
. Results of the Jackknife analysis. Numbers on the branches indicate percentage boostrap values.
Comparative comments.
Agrodes
was established by
Nordmann (1837)
, who distinguished it from the species then placed in
Plochionocerus
. Some authors (
Erichson 1839
,
Laporte 1840
,
Gemminger & Harold 1868
,
Blackwelder 1944
), however, synonymized it with
Sterculia
, whereas others (
Erichson 1847
,
Lacordaire 1854
) considered it valid, treating
Sterculia
and
Araeocnemus
as synonyms of
Agrodes
or as its subgenera (
Bernhauer & Schubert, 1914
).
Sharp (1876
,
1885
) was the first author to distinguish
Agrodes
from
Sterculia
(now
Plochionocerus
) and
Renda
(named by him as
Plochionocerus
) and provided characters (such as the elongate head and development of the prosternum) that have been important for our decision to consider
Agrodes
a distinct genus.