Corresponding author: Kelly B. Miller (
Academic editor: M. Michat
The Neotropical diving beetle genus
El género neotropical de escarabajos aquáticos
Miller KB (2016) Revision of the Neotropical diving beetle genus
In general, members of this group are rarely collected with most specimens in collections found using lights at night. Only a few species have been collected in long series, though some of these series do include many species A few specimens have been collected from forest streams or stream margins, but little to nothing else is known of the biology of most
New species have been described regularly over several years (
Female genitalia were examined by first relaxing a specimen in near boiling water. A pin was then inserted into the end of the abdomen and moved along the suture between abdominal ventrites VI and VII and between tergites VII and VIII. The lateral junction of these sclerites was then cut with microscissors. Fine microforceps were then inserted into the abdomen and the female internal genital structures were grasped and the entire internal abdominal apex removed. These structures were then placed into a small glass tube with a 10% KOH solution. This tube was then placed in near boiling water to heat the KOH for about 10 minutes to macerate the soft tissues. The remaining structures were removed and placed in a weak acetic acid solution and then rinsed in much distilled water. Structures were stained using an aqueous solution of Chlorazol Black®. Structures were then placed into a genitalia vial in glycerin and mounted on the pin with the specimen. Female genitalia were examined in water. Examination in glycerin is not preferable since structures collapse, but in water they expand and are easily visible.
Female genitalia are not described for all species here either because females are not available, the genitalia are damaged due to previous attempts to dissect the specimen, or female specimens are determined to be too rare or valuable to risk a dissection attempt which is often somewhat destructive to the specimen.
total length greatest width across elytra greatest width of pronotum greatest width of head distance between eyes
Florida State Collection of Arthropods, University of Florida, USA (P. Skelley)
Kelly B. Miller Collection, Museum of Southwestern Biology, University of New Mexico, USA
Museo del Instituto de Zoología Agrícola Francisco Fernández Yépez, Universidad Central de Venezuela, Maracay, Venezuela (L. Joly)
Museum of Southwestern Biology Division of Arthropods, University of New Mexico, Albuquerque, NM, USA (K.B. Miller)
Museu de Zoologia da Universidade de São Paulo, São Paulo, Brasil (S. Casari)
National Zoological Collection of Suriname, Paramaribo, Suriname (P. Ouboter)
Naturalis Biodiversity Center and Leiden University, The Netherlands (H. Huijbregts)
Snow Entomological Collection, University of Kansas, Lawrence, Kansas, USA (A.E.Z. Short)
United States National Collection of Insects, Smithsonian Institution, Washington, DC, USA (T. Erwin)
Label data for primary type specimens is reported verbatim. All other label data, including for paratypes, is reported in a standardized format. All paratypes of new species have attached a blue label with a black line border bearing the species name.
Relatively little is know of the natural history of most members of the group. A great many museum specimens were collected at lights. Other specimens were collected from forest streams, often in low numbers. Occasionally, longer series have been found in tropical forest streams. Larvae and other aspects of their natural history have not been described.
The first species of
Monophyly of
Two species,
1 | Size very small ( |
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– | Size larger ( |
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2(1) | Lateral elytral carina short (<1/4 elytral length) (Fig. |
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– | Lateral elytral carina long (≥1/4 elytral length) (Fig. |
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3(2) | Basal half of elytron approximately concolorous on disc, without distinct maculae (Fig. |
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– | Basal half of elytron with distinctive maculae or fasciae (e.g. Fig. |
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4(3) | Dorsal and ventral surfaces nearly concolorous, without maculae, though color may vary somewhat in intensity across surfaces (as in Fig. |
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– | Dorsal and ventral surfaces red to red-brown, apical half of elytron with irregular, subtriangular maculae and apex of elytron pale orange to yellow, pronotum of many specimens lighter orange, lighter in color than elytron (as in Fig. |
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5(4) | Size larger ( |
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– | Size smaller ( |
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6(5) | Size smaller ( |
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– | Size larger ( |
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7(4) | Eyes entire (Fig. |
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– | Eyes entire; male and female similar in shape, both apically evenly tapered |
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8(7) | Eyes entire in dorsal aspect (Fig. |
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– | Eyes emarginate in dorsal aspect (Fig. |
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9(7) | Prosternal process with lateral margins subparallel, slightly concave, posteriorly broadly rounded (Fig. |
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– | Prosternal process anteriorly with prominent, lateral lobes, posteriorly distinctly tapered to rounded apex (as in Fig. |
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10(9) | Male median lobe bilaterally symmetrical in ventral aspect, apex rounded (Fig. |
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– | Male median lobe bilaterally asymmetrical in ventral aspect, apex obliquely truncate (Fig. |
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11(3) | Prosternal process very broad (length/width < 1.8), lateral margins rounded, and broadly concave medially (as in Fig. |
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– | Prosternal process narrower (length/wdith > 2), lateral margins variable, subparallel to sinuate, narrowly longitudinally concave medially (as in Fig. |
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12(11) | Prosternal process very broad, apically broadly subtruncate (Fig. |
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– | Prosternal process broad but elongate with lateral margins broadly rounded and apex acuminate (Fig. |
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13(11) | Prosternal process anteriorly with prominent, laterally-projecting lobes, lateral carinae distinctly convergent to narrowed apex (Fig. |
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– | Prosternal process anteriorly without or with weak, laterally-projecting lobes, lateral carinae subparallel to rounded apex (as in Fig. |
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14(13) | Elytron with two large pale regions, one quadrate macula laterally at anterolateral margin and one subtriangular, subapical maculae (Fig. |
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– | Elytral maculae not consisting of two large pale regions, either consisting of complex fasciae (as in Fig. |
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15(14) | Elytral pattern complex, fasciate (Fig. |
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– | Elytral pattern simpler, with maculae subbasally near suture and lateral margin, submedially from lateral margin to near suture, and apically (as in Fig. |
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16(15) | Prosternal process shallowly depressed medially (Fig. |
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– | Prosternal process deeply depressed medially; medial portion of metacoxae with distinct longitudinal channels which are margined; dorsal pattern fasciate (Fig. |
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17(2) | Posterior apices of metaventrite carinae located well mediad of anterior apices of metacoxal lines (Fig. |
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– | Posterior apices of metaventrite carinae near anterior apices of metacoxal lines, at most slightly mediad, but generally metaventrite carinae and metacoxal lines approximately continuous (Fig. |
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18(17) | Body elongate, slender ( |
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– | Body elongate, but generally somewhat more robust ( |
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19(18) | Overall length longer ( |
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– | Overall length shorter ( |
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20(17) | Lateral elytral carina extending nearly to elytral apex (Fig. |
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– | Lateral elytral carina not extending nearly to elytral apex (Fig. |
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21(20) | Prosternal process relatively slender (length/width > 2), lateral margins abruptly narrowed medially (Fig. |
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– | Prosternal process broad (length/width < 2), lateral margins not abruptly narrowed medially, instead process broad throughout length (Fig. |
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22(21) | Metaventral platform strongly constricted, length of metaventral platform long compared with narrowest distance between carinae immediately posteriad to mesocoxae (length/width of constriction > 5, greatest width/width of constriction > 2.5) (Fig. |
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– | Metaventral platfrom not strongly constricted, length of metaventral platform shorter compared with narrowest distance between carinae immediately posteriad to mesocoxae (length/width of constriction < 5, greatest width/width of constriction < 2.5) (Fig. |
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23(22) | With distinctive maculae on elytra subbasally, subapically, and apically, basal macula distinct, transverse, extending nearly to suture (Fig. |
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– | With elytral maculae indistinct, if present, mainly limited to subapical and apical indistinct pale areas, subbasal area of elytra of some specimens with indistinct, vague pale area |
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24(23) | Pro- and mesotibia slender, without subapical emargination along dorsal margin (Fig. |
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– | Pro- and mesotibia broad, with subapical emargination along dorsal margin (Fig. |
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25(24) | Length > 3.0 mm |
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– | Length < 3.0 mm |
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26(22) | Metacoxal lines broadly divergent anteriorly, approximately continuous with metaventrite/ metacoxal suture (Fig. |
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– | Metacoxal lines divergent or not, but intersecting metaventrite/metacoxal suture at distinct angle (Fig. |
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27(26) | Greatest width of pronotum relatively narrow with respect to greatest width across elytra ( |
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– | Greatest width of pronotum relatively broad with respect to greatest width across elytra ( |
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28(27) | Prosternal process anteriorly with distinctly projecting lateral lobes, abruptly constricted medially (Fig. |
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– | Prosternal process with lateral margins approximately continuously curved, without prominent lobes, not constricted (Fig. |
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Peru, near Ituitos, from the Amazonas.
This species is difficult to diagnose from others since specimens were not available for examination, but based on the description and illustrations by
This species is known only from the type locality near Iquitos, “from the Amazonas,” Peru. (Fig.
Nothing is known of the natural history of this species.
The specimens on which this species (and
No specimens were examined of this species, and the treatement here is based on the description by
Suriname, Carolina Creek, 10km S Zanderij.
This is a very distinctive species which is dorsally nearly concolorous red (Fig.
Specimens have been collected from along a river margin, in a large sandy creek, a muddy oxbow pond, in detrital pools by a forest stream, and from lights at night. The species appears to be mainly associated with margins of forest rivers.
Although the holotype of this species (in Rijksmuseum van Natuurlijke Historie, Leiden) was not examined, there is little doubt as to the identity of the species. That said, many specimens do not have the anterior angles of the pronotum nearly as angulate as others. In some of these specimens the anterior margin of the clypeus is not as strongly margined. The more angulate specimens are generally found in the eastern part of the range. The male genitalia are identical, and other features, such as the well-marked lateral elytral carina, the shape of the prosternal process, metaventrite carinae, and metacoxae are also the same. Even so, a greater sampling may eventually reveal that more than one species is actually involved.
Holotype not examined. Other non-type specimens examined (84 total):
Species | KUNHM accession numbers |
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SEMC0908225, SEMC0930584, SEMC0930585, SEMC1088259, SEMC1088302, SEMC1088325, SEMC1088329, SEMC1089613, SEMC1089618, SEMC1234318, SEMC1234323, SEMC1234327 |
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SEMC0913238 |
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SEMC1080468, SEMC1080471 |
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SEMC0854749, SEMC0915510 |
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SEMC1088337 , SEMC1088338, SEMC1088339, SEMC1088342, SEMC1088346, SEMC1088347, SEMC1088351 |
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SEMC0915690, SEMC1088262, SEMC1088263, SEMC1088284, SEMC1088286, SEMC1088295, SEMC1088296, SEMC1088298, SEMC1088303, SEMC1088316, SEMC1088321, SEMC1088322, SEMC1088328, SEMC1088330, SEMC1088331, SEMC1088332, SEMC1088334, SEMC1088335, SEMC1088344 |
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SEMC0964975, SEMC0964987 |
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KUNHM SEMC0964970, KUNHM SEMC0964971, KUNHM SEMC0964975, KUNHM SEMC0964984, KUNHM SEMC0964985, KUNHM SEMC0964986, KUNHM SEMC0964989, KUNHM SEMC0964991 |
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SM0842821, SM0842840 |
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SEMC1080472, SEMC1080473, SEMC1080474, SEMC1080475, SEMC1080476 |
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SM0842832, SM0843017, SM0843053, SM0843078, SM0843079, SM0843080, SM0843127, SM0843127, SM0843130, SM0843131, SM0843138, SM0843142, SM0843143, SM0843144, SM0843146, SM0843151, SM0843153, SM0843166, SM0843170, SM0843172, SM0843175, SM0843176, SM0843179, SM0843186, SM0843187, SM0843188, SM0843189, SM0843195, SM0843197, SM0843198, SM0843199, SM0843200, SM0843201, SM0843202, SM0843203, SM0843227, SM0843228, SM0843229, SM0843245, SM0843246, SM0843247, SM0843276, SM0843306, SM0843308, SM0843309, SM0843312, SM0843316, SM0843317, SM0843318, SM0843320, SM0843327, SM0843329, SM0843337, SM0843338, SM0843340, SM0843347, SM0843348, SM0843354, SM0843355, SM0843357, SM0843359 |
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MIZA0001487, SEMC0914432 |
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SM0843163, SM0843182, SM0843268, SM0843269, SM0843299 |
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SEMC1088261, SEMC1089221 |
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SEMC0915670 |
This species is elongate and dorsally and ventrally nearly concolorous red, though some specimens have indistinct pale, subtriangular maculae subapically and the apex of the elytron more pale (Fig.
This species has been collected from Para, Brazil north through Suriname and Guyana to southern Venezuela (Fig.
Specimens have been collected from blacklights in tropical forests and from the margins of a river and a flooded forest stream.
Although the holotype of
This species, though widespread, is rarely collected and has not been collected in long series.
Holotype of
Other non-type specimens examined (6 specimens):
Venezuela, Territoria Federal Amazonas, Cerro de la Neblina, basecamp,
This species is moderately elongate and dorsally and ventrally nearly concolorous red, except with small pale, subtriangular maculae subapically and the apex of the elytron is narrowly pale (Fig.
This species is named
This species is known only from Cerro de la Neblina, Amazonas, Venezuela (Fig.
Holotype: ♂ in
Paratype, 1 total.
Brazil, Pará State, Cachimbo.
Nothing is known of the habitat of the species.
Only the male holotype specimen was examined of this species.
The holotype male specimen is in
Venezuela, Amazonas, Cerro de la Neblina, basecamp,
This species has the lateral elytral carina relatively short, present just at the humeral angle, and the body overall approximately concolorous dark red (Fig.
This species is named
The two specimens in the type series were collected from leaf pack from among rocks in a small rainforest stream.
The holotype male is in
Paratypes, 4 total.
Venezuela, Amazonas, Cerro de la Neblina, basecamp,
This species is dorsally shiny and concolorous dark red (Fig.
This species is named
This species is known only from the type locality area, Cerro de la Neblina, Amazonas, Venezuela (Fig.
Specimens have been collected from along the margins and from rocks in rapids in a forest river and from a muddy oxbow pond in a rainforest clearing.
The holotype male in
Paratypes, 120 total.
Venezuela, Amazonas, Cerro de la Neblina, 1km SE basecamp,
This species differs from others by being dorsally nearly concolorous but with indistinct paler regions subapically and apically (Fig.
This species is named
This species is known only from Cerro de la Neblina, Amazonas, Venezuela.
One specimen was collected from the margin of a river and the other known specimens from a blacklight.
The holotype male is in
Paratype, 1 total.
Suriname, Sipaliwini District, Tafelberg Summit near Augustus Creek Camp,
This species is moderately elongate and dorsally and ventrally nearly concolorous red, without maculae on the elytra (Fig.
This species is named
This species is known only from the type specimens from the Tafelberg in Sipaliwini District, Suriname (Fig.
Specimens were collected from “forested creek margins.”
The holotype male is in
Paratype, 1 total.
Brazil, Rio Gurupi, 12–15km E Caninde-Igarape Coraci.
This species is dorsally dark brown with distinctive, irregular fasciae on the elytra (Fig.
This species is named
Nothing is known of the natural history of this species.
The holotype male is in
Paratypes, 2 total.
Ecuador, Provincia de Napo, Limococha on Rio Napo,
This species is dorsally largely red with the pronotum orange and the elytral apex, lateral margins, and a moderately well-defined macula at about 2/3 length of elytron (Fig.
This species is named
This species is known only from the type locality in Provincia de Napo, Ecuador (Fig.
The single known specimen was collected at a black light.
The male holotype is in
Surinam, District Brokopondo, Brownsweg.
In addition to the type locality in Brokopondo District, Suriname, this species is known from two sites, one in Bolivar State, Venezuela and another in Sipaliwini District, Suriname (Fig.
The type specimen had been dissected for examination in this study, and the base of the male median lobe and the lateral lobes were damaged and could not be illustrated. Other than the male type specimen, only two female specimens are known for this species, they are very similar to each other and distinct from all other species. They were also collected quite some distance from each other. Despite the lack of knowledge of males, it seems likely that future association of specimens with this species will not be problematic.
Holotype: ♂ in
Ecuador, Pastaza, Provinica Tzapino, 32km NE Tigueno,
This species is named
This species has been collected from blacklight traps. Nothing else is known about their habitat.
The holotype is in
Paratypes, 24 total.
Suriname, Sipaliwini District, Camp 1, Upper Palumeu,
This is a red species with the head and pronotum often somewhat lighter red and with moderately well-defined pale maculae on the elytra (Fig.
This species is named
The type series was collected from a large, sandy creek.
The holotype male is in
Paratypes, 6 total.
Venezuela, Amazonas, Cerro de la Neblina, basecamp,
This species is named
This species is found in Amazonas, Venezuela and in southern Suriname (Fig.
Specimens have been collected along the margins of a forest river, from a large, sandy creek, and at UV light.
The male holotype is in
Paratypes, 83 total.
Suriname, District Brokopondo, Brownsweg.
This species is robust and broadly rounded with a distinctive dorsal pattern of maculae and fasciae (Fig.
This species is known from Venezuela (Fig.
Specimens have been collected along a forest river and at lights.
This species is named
See below under
Holotype in
Paratypes, 5 total.
Peru, Madre de Dios, Rio Tambopata Reserve, 30km SW Puerto Maldonado.
This species is part of a group including
This species is named
This species is known only from one locality in Tambopata Reserve, Peru (Fig.
The type specimens were collected from subtropical moist forest.
Two female specimens were examined of this species. Although ordinarily it is ill advised to describe new species of
The holotype and one paratype were examined. The holotype female is in
Paratype, 1 total.
Venezuela, Territorio Federal Amazonas, Cerro de la Neblina, basecamp,
This is a distinctive, elongate, dorsally maculate species (Fig.
This species is named
Specimens were collected “seined from rocks in rapids” and “netted along margins” of the Rio Baria. They have also been found in creeks and at a blacklight in a rainforest.
Holotype: ♂ in
Paratypes, 110 total.
Venezuela, Amazonas, Cerro de la Neblina, basecamp,
This is the smallest
This species is named
This species is found only in Amazonas, Venezuela (Fig.
Nearly all the known specimens were collected at black light.
This extremely small
The holotype male is in
Paratypes, 5 total.
Peru, near Ituitos, from the Nanay.
This species is very similar to (or possibly identical with)
This species is known only from the type locality near Iquitos, “from the Nanay,” Peru (Fig.
The single specimen was found “from the Nanay,” which is a large tropical river, though it is not clear that the specimen was specifically collected from the river or, instead, from the region.
The specimen on which this species was based was collected during the Catherwood Foundation expedition to Peru. The type material was not found in either the Academy of Natural Sciences of Philadelphia (
No specimens were examined of this species, and the treatement here is based on the description by
This is a relatively compact species with the dorsal coloration ranging from red to red-brown, sometimes with larger, indistinct pale areas or smaller, more distinctive pale regions (Fig.
This species is known from Guayana and southern Venezuela to Brazil and south to Paraguay (Fig.
Examination of the male holotype specimens of
The
The
Additional non-type material examined (15 total).
Venezuela, Amazonas State, Communidad Cano Gato, Rio Sipapo,
This species has the lateral elytral carina relatively short, present just at the humeral angle (Fig.
This species is named
The two known specimens were collected from a sandy forest stream with considerable plant material (leaves, branches, etc) in the margins.
The male holotype specimen is in
Paratypes, 1 total.
Guyana, Mazaruni-Potaro District, Takutu Mountains,
This species is largely red dorsally (Fig.
This species is known only from the Takutu Mountains of northern Guyana (Fig.
The single known specimen was collected from a blacklight in a forest clearing near some streams.
The holotype male in
Brazil, Pará State, Cachimbo.
Specimens of this species are among the largest
The species is known only from the type locality in Para, central Brazil (Fig.
Nothing is known of the habitat of this species.
Only the female holotype in
Guyana, Mazaruni-Potaro District, Takutu Mountains,
This species is part of a group including
Specimens have been collected from blacklights and several forest habitats including muddy oxbow lakes, pools and leafpacks in whitewater streams, and stream margins.
Two female specimens from Paraguari, Paraguay (
The holotype male in
Other non-type specimens examined, 48 total.
Suriname, District Brokopondo, Brownsweg.
This species is known only from a couple localities in Suriname (Fig.
A series of specimens was collected along the margins of a forest creek.
This species and
Holotype: ♂ in
Brazil, Pará, Rio Cupari, Igarapé Ingatuba.
This species is known from central Brazil and southern Venezuela (Fig.
This species was collected from “margem esquedra, entre detrito fibrosito” (
The holotype (in BMNH) was not examined, but the male paratype (of one male and two female paratypes,
Holotype not examined. Non-type specimens examined, 64 total.
Guyana, Mazaruni-Potaro District, Takutu Mountains,
This species has the elytron red with a moderately well-defined yellow macula at about 2/3 length of elytron (Fig.
Specimens have been collected at a blacklight in a forest clearing near streams.
The holotype male in
Other non-type specimens examined, 3 total.
Suriname, Carolina Creek, 10km S Zanderij.
This species is known from Suriname and Amazonas, Venezuela (Fig.
This species has been collected from waterholes in a forest stream, tiny forest pools, large detrital pools, a large, sandy creek, and along a stream.
The holotype (in Rijksmuseum van Natuurlijke Historie, Leiden,
Specimens examined, 17 total.
Suriname, Sipaliwini Districct, Camp 1 on Kutari River,
This species is part of a group including
This species is named
This species is known only from one locality in Suriname near the Kutari River (Fig.
The one known specimen was collected at a UV light at night.
Only the holotype male was examined in
Suriname, Brokopondo District, Brownsweg.
This species was described by
Holotype: ♂ in
Thanks to S. Casari, T. Erwin, H. Jijbregts, L. Joly, P. Ouboter, A.E.Z. Short, and P. Skelly for generous loan of specimens, including types. J. Weintraub (Academy of Natural Sciences of Philadelphia) and P. Perkins (Museum of Comparative Zoology, Harvard) generously searched for the Spangler types. Thanks to Q. Arias, J. Camacho, J. Clavijo, M. García, and L. Joly for much help in the field. A.E.Z. Short provided extensive friendship and collaboration and organized specimens, specimen data and field work. Portions of this work were funded by NSF grants #DEB–0845984 and #DEB-1353426 (K.B. Miller, PI) and #DEB–0816904 (A.E.Z. Short, PI; K.B. Miller, co–PI).