Taxonomy of Guatemalan water beetles in the genus Hydrochus (Coleoptera: Hydrochidae)
Author
Perkins, Philip D.
text
Acta Entomologica Musei Nationalis Pragae
2020
2020-04-23
60
1
291
301
journal article
21739
10.37520/aemnp.2020.016
6f4e1328-0bba-4f1c-aa66-4c1fe1fda040
1804-6487
3879760
45563A23-8582-4C53-81F3-591948E7A74D
Hydrochus debilis
Sharp, 1882
(
Figs 1
,
2
,
8
)
Hydrochus debilis
Sharp, 1882: 89
.
Type material examined.
LൾǤŦƟŦYPൾ (hereby designated,
Fig. 8
): male (
NHM
): ‘
Hydrochus debilis
Type D. S.
Chontales
.
Nicaragua
Janson // [male symbol] //
LECTOTYPE
[blue disc] //
Chontales
,
Nicaragua
. Janson. // B.C.A. Col. I. 2.
Hydrochus debilis, Sharp.
// HABITUS / GENIT. DIGITAL IMAGES captured 2020 P.D. Perkins // [red]
LECTOTYPE
Hydrochus debilis
Sharp
desig. P. D. Perkinsʼ. PARAĿൾǤŦƟŦYPൾ: female (
NHM
): ‘
Hydrochus debilis
Type D. S.
Chontales
.
Nicaragua
// [female symbol] //
PARALECTOTYPE
[blue disc] //
Chontales
,
Nicaragua
. Janson. // B.C.A. Col. I. 2.
Hydrochus debilis, Sharp.
// LECTOPARATYPE
H.debilis
by J. L. Hellman 75 // [yellow]
PARALECTOTYPE
Hydrochus debilis
Sharp
desig. P. D. Perkinsʼ.
Additonal material examined
(
15 spec.
).
GUATEMALA
:
Izabal
,
1 mi.
N. Morales.Km 239 Atlantic Hwy,
16–18.viii.1965
, leg. Paul J. Spangler (1:
NMNH
);
20 mi.
SW Puerto Barrios,
16.viii.1965
, leg.Paul J. Spangler (4:
NMNH
);
28 mi.
SW Puerto Barrios,
16.viii.1965
, leg.Paul J. Spangler (1:
NMNH
); Rio Dulce Fy.,
2.vii.1974
, leg. W. E. Steiner (9:
NMNH
).
Lectotype
designation.
The NHM kindly provided two
syntypes
of
Hydrochus debilis
, which are part of the Sharp
Biologia Centrali-Americana
types collection. The
syntypes
consist of one male and one female. I have selected the male to serve as
lectotype
and labeled it as such, and provide images of the habitus, male genitalia, and labels of that specimen (
Figs 1
,
2
,
8
). The other
syntype
has been labeled
paralectotype
. One additional specimen provided by the NHM as ‘Possible typeʼ is a different species, from
Mexico
. One of the
syntypes
bears a
lectotype
label, by
J. L. Hellman
, but this designation was never published.
This
label has been reversed and “unpub.” written on the reverse side.
Differential diagnosis.
Among Guatemalan species,
H. debilis
is recognized by the combination of moderate size (ca.
2.69–3.08 mm
), the densely punctate pronotum with deep foveae, and the elytral sculpture, each elytron having four raised interstriae: 3
rd
slightly raised over basal ¼, 4
th
raised in area anterior to large callus of 5
th
, 5
th
raised from about anterior ¼ to midlength, and usual callus of 5
th
. The distinctive male genitalia (
Fig. 2
; described below) are also diagnostic.
Fig. 2.
Hydrochus debilis
Sharp, 1882
, habitus and male genitalia of lectotype.
Redescription.
Habitus as illustrated (
Fig. 2
). Size (in mm):
Lectotype
: body (length to elytral apices / width) 2.88 / 1.04; head width 0.69; pronotum length / width 0.75 / 0.71; PA 0.67; PB 0.56; elytra length / width 1.85 / 1.04. Body size moderate (ca.
2.69–3.08 mm
in Guatemalan specimens). Dorsum dark grey to black, with very slight if any iridescence, elytra with black spots. Legs dark brown, with tibiofemoral joints slightly darker. Punctation on elytra ca. 2–4× that of pronotum. Elytra interstriae ca. 0.5–1.0× strial puncture diameter. Interstria 9
th
more convex than others, overhanging 10
th
interstria. Callus on 5
th
in usual area, large, very strongly raised.
Pronotum length ca. equal width, widest at ca. anterior 1/3, narrowed at base, sides sinuate, minutely denticulate; anterior margin slightly bisinuate; depressions deep, reliefs sharply raised, depressions and reliefs densely punctate.
Elytra with spaces between strial punctures narrow ridges to ca. 0.5× their diameter; 3
rd
interstria slightly raised over basal fourth; 4
th
interstria raised in area anterior to callus of 5
th
; 5
th
interstria raised from about anterior fourth to midlength, raised area separated from callus of 5
th
by very slight depression; apices rather sharply conjointly rounded in dorsal view, in lateral view outer margin with moderate angulation.
Fig. 3.
Hydrochus directus
sp. nov.
, habitus and male genitalia of holotype.
Male genitalia (
Fig. 2
). General characters: paramere tips moderately large, extending beyond distal tip of aedeagus, sagittate, distal ends pointed, lateral margins between
plsa
and distal end slightly emarginate, medial margins of tips very slightly arcuate toward midline and well separated from lateral margins of aedeagus; parameres in dorsal/ventral views constricted at base of tips and dorsally with low ridge; parameres in dorsal/ventral views much wider at widest point than tips; parameres in lateral view wide, sinuate, and tapering to sharp tips; aedeagus greatest width at
adbl
, shaft (portion of aedeagus distal to
adbl
) in dorsal/ventral views very narrow, almost parallel-sided; aedeagus dorsal margin sinuate in lateral view; basal piece shorter than parameres, with rim of orifice sclerotized.
Dorsal surface:
adtl
located at about distal fifth of aedeagus;
pdmm
very slightly narrowly overlapping
alm
at about midlength of aedeagus;
adbl
very large, much wider than paramere area lateral to
adbl
, distinctively shaped.
Ventral surface:
pvmm
overlapping
alm
at base;
pwsa
near base.