Amazonopsis theranyi

Barr, Cheryl B., 2018, Amazonopsis, an unusual new genus of riffle beetle from South America with two new species (Coleoptera, Elmidae, Elminae), ZooKeys 803, pp. 71-92: 74-83

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Amazonopsis theranyi

sp. n.

Amazonopsis theranyi  sp. n. Figs 1, 2, 3, 4, 5, 6, 7-8

Type material.

Holotype male deposited in MUSM, labeled: "PERU: [Dpto.] Madre de Dios / Tambopata, Quebrada / Santo Rosario, el. 230 m / −12.8788, −69.7396 / 29-V-2012, T. Gonzales // collected from artificial / leaf pack of Inga edulis  / leaves, ACEER-Stroud / project 2012-2013 // HOLOTYPE / Amazonopsis  / theranyi  Barr" [red label, handwritten]. Allotype female deposited in MUSM, labeled "PERU: [Dpto.] Madre de Dios / Tambopata, Quebrada / Santo Rosario, el. 230 m / −12.8788, −69.7396 / 4-VII-2012, T. Gonzales // collected from artificial / leaf pack of Inga edulis  / leaves, ACEER-Stroud / project 2012-2013 // ALLOTYPE / Amazonopsis  / theranyi  Barr" [red label, handwritten]. Paratypes (2) locality as above, 29-V-2012 [yellow labels, printed] (1 M & 1 F, EMEC).

Additional material examined.

french guiana / ca. 4 km ESE Saül / Cr.[ique] Nouvelle France / 03.6063, −53.1762 / 9-XI-2016, C. B. Barr // Parc Amazonien / de Guyane just / below Point Chaud / coll. from leaf pack (1 F, EMEC); as above, ca. 4.5 km SE Saül / Cr.[ique] Nouvelle France / 03.5972, −53.1779 / 9-XI-2016, C. B. Barr // Parc Amazonien / de Guyane at / Courant Doublé / coll. from leaf pack (1 F, MNHN); VENEZUELA. T. F. Amaz.[onas] / Cerro de la Neblina / 1 km S Basecamp / 0°50'N, 66°10'W / 140 m, 8 Feb. 1985 // Small pool full of / dead leaves; rain- / forest ridge / W. E. Steiner & R. Halling collrs. (1 M, USNM).


Amazonopsis theranyi  males (Figs 1, 2, 4, 5) differ from those of A. camachoi  (in parentheses) (Figs 9, 10) by the following characters: elytra with low protuberances at humeral angles (protuberances prominent), third elytral interval slightly raised (prominently raised), all intervals with fine, sparse setae (odd-numbered intervals with longitudinal rows of thick setae); protarsomere 5 with sparse setae barely extending to base of claws (two apical clusters of long, curved setae extending well beyond base of claws); protarsal claws elongate, moderately curved (short, strongly curved), outer claw without inner tooth (with inner tooth), claws of similar width (outer claw narrower); outer mesotarsal claw shorter than tarsomere 5 (as long as tarsomere 5) and 2 × wider than inner claw (at least 3 × wider); distance between prosternal spines narrower than labrum (as wide as); metaventrite with pair of small, tooth-like processes (prominent, lobe-like); male genitalia with penis as wide at base as paramere base (much wider than), penis narrower at midlength than paramere at midlength (wider than), phallobase length subequal to that of parameres (longer than).


Holotype male. Length, 4.20 mm; width, 1.90 mm. Cuticle mostly covered with pale, thin microreticulate layer dorsally and ventrally, with thicker, glossy, golden-yellow plastron ventrolaterally on thoracic sterna and abdominal ventrites; cuticle shiny, dark reddish-brown where exposed. Antenna. Yellow-brown. Antennomeres 1-10 clavate, antennomere 11 fusiform; antennomeres 1 and 2 each stouter than 3-10 which are of similar size and shape; antennomeres 3-10 each with dense tuft of setae at apicoventral margin, overlapping base of next; antennomere 11 with an elongated patch of short setae near the ventral apex. Head. Vertex, frons and clypeus covered with pale, microreticulate plastron and broad, flat, yellow setae. Clypeus dark brown, barely emarginate at center of apical margin, setae slightly less dense than on vertex and frons. Labrum dark brown, barely emarginate, apicolateral angles broadly rounded; surface with small, evenly spaced punctures and short, fine setae; apical and lateral margins with fringe of pale, dense setae, longest laterally. Mandible with three short, rounded, apical teeth. Maxillary palpus yellow-brown; palpomere 4 slightly flattened and curved, longer than 1-3 combined, with oval patch of sensillae at apex. Labial palpus with palpomeres 1 and 2 short, dark brown; palpomere 3 longer than 1 and 2 combined, yellow-brown, ovoid and moderately flattened. Pronotum. Length, 1.20 mm; width, 1.50 mm. In dorsal view, lateral margins coarsely granulate, unevenly arcuate; anterior margin trisinuate, strongly arcuate at middle; anterolateral angles acute, depressed. In lateral view, moderately convex. Disc covered with pale microreticulate plastron and deep, closely spaced, coarse punctures; punctures larger towards the lateral margins, smaller towards the midline; punctures generally spaced a diameter apart; punctures lined with plastron and associated with very short, erect setae; anteromedial disc and lateral areas with broad, flat, recumbent, yellow setae. Center of midline with narrow, lightly impressed, bare, longitudinal line; length about ½ that of pronotum. Scutellum subcircular. Elytron. Length, 3.00 mm; width, 0.95 mm. Surface covered with pale, thin microreticulate plastron, abraded at center of disc; punctures striate, deep, coarse, lined with plastron; intervals of striae with fine, sparse setae. Humeral angle with low, knob-like protuberance; base of third interval slightly swollen and raised; lateral margins smooth, recurved with narrow, longitudinal band of hypomeron plastron visible; shallow sulcus about one interval wide adjacent to lateral margin, extending from humeral angle to apical 1/5; elytra constricted at apical 1/5 at point of linkage with abdominal ventrite 4 lateral lobe; apex evenly rounded, moderately produced. Legs. Femora and tibiae covered by thin layer of shiny, pale yellow plastron, sparsely setose and shallowly punctate; tarsus red-brown, without plastron. Procoxa posterior surface coarsely punctate; dense patch of long, golden-yellow setae present on lateral face. Prothoracic leg with tibia longer than femur, tarsus shorter; profemur with oval patch of long, recumbent, golden-yellow setae on anterior surface near base; protibia with pair of cleaning fringes nearly ½ as long as tibia, posterior fringe slightly shorter; protarsus with tarsomeres 1-4 bearing dense tufts of moderately long setae in two rows at apicoventral margins; tarsomere 5 longer than the others combined, with moderately long setae on ventral surface and a few longer, golden-yellow setae at apex which barely extend over base of claws. Protarsal claws dissimilarly shaped, long, laterally flattened, sharply acute; inner claw enlarged, base bent outward, tip bent ventrally; outer claw shorter, base and tip not bent. Mesocoxa coarsely punctate and granulate; dense patch of long, golden-yellow setae present on lateral face and adjacent sternum. Mesothoracic leg similar to prothoracic leg except mesofemur with elongate patch of long, recumbent golden-yellow setae on posterior surface extending from near base to half femoral length; mesotibia with pair of cleaning fringes nearly ⅔ as long as tibia. Mesotarsal claws dissimilarly shaped, much longer than protarsal claws, laterally flattened, sharply acute; outer claw enlarged, slightly curved, bent about 90° at base then flattened and widened, more than 2 × wider than inner claw; inner claw slightly shorter and much narrower. Metacoxa medial surface with longitudinal, sulcate row of coarse, deep punctures; posterolateral surface with dense patch of long, golden-yellow setae. Metathoracic leg similar to other legs except tibia much longer than femur; single cleaning fringe on posterior face about ⅔ as long as tibia; both claws slightly flattened but basically unmodified, stout, shorter than pro- and mesotarsal claws. Venter. Hypomeron with large, coarse, closely spaced punctures, more than 2 × diameter of lateral pronotal punctures; ventral margin with broadly rounded lobe directed toward coxa; longitudinal band of golden-yellow plastron present on central ventral margin. Prosternum anterior margin raised, bearing two small, ventrally directed spines; distance between spines narrower than labrum; anterolateral margin behind each eye having a small, nearly semicircular notch; prosternal process about 2 × as long as wide, with elevated margin; prosternal disc covered with pale, microreticulate plastron, scattered broad, flat, yellow setae, and large circular punctures spaced slightly less than a puncture diameter apart; golden-yellow plastron present laterally. Mesoventrite depressed between mesocoxae; punctation similar to that of prosternum; disc with pale, microreticulate plastron, mesepimeron with band of dense, golden-yellow plastron. Metaventrite depressed between mesocoxae; discrimen sulcate; posteromedial margin with two low, obtuse, ventrally directed processes; punctures more oval than circular in shape, closer together near midline; disc with pale yellow plastron except along midline, most dense laterad and on metepisternum. Abdomen with pale yellow plastron on all surfaces except for areas of bare, shiny cuticle at midline; ventrites 1-4 non-setose, ventrite 5 with fine, scattered setae; punctures not as large as those on thoracic sternites, becoming progressively smaller with each succeeding ventrite; punctures evenly spaced but less dense than on thoracic sternites; ventrite 1 anterior margin between metacoxae smoothly arcuate; ventrites 1-4 moderately convex at lateral ¼; ventrite 5 with two basolateral swellings each bordered by a shallow depression, apical ⅓ depressed and margin broadly rounded. Genitalia (Fig. 2). Elongate, narrow. Phallobase as long as parameres, narrowest at basal ⅓. Paramere in dorsal and ventral views (Fig. 2a, c) sinuous, moderately narrow, narrowest ⅔ distance from base; apex bluntly rounded, clasping tip of penis; paramere in lateral view (Fig. 2b) mostly parallel-sided, apical 1/5 expanded, paddle-like, tip curved slightly ventrad; inner surface shallowly canaliculate. Penis barely shorter than parameres, thin; base about as wide as paramere base, gradually narrowed to just past midlength then widening slightly; apex pointed; corona and fibula absent; basal apophyses about 1/4 as long as phallobase.

Allotype female. Length (excluding head), 4.25 mm; width, 2.00 mm. Pronotum 1.25 mm long, 1.55 mm wide; elytron 3.15 mm long, 1.00 mm wide. Secondarily sexually dimorphic as follows: pronotum with two, moderately large, oval perforations of the cuticle on either side of midline; all claws normal, not modified, shorter than those of males; anterior margin of prosternum without paired spines; posterior margin of metaventrite without paired, ventrally directed processes. Otherwise, similar to the male.


The most striking variation is the strong secondary sexual dimorphism exhibited by males and females. Males (Figs 1, 4) have the following characteristics which females (Fig. 3) lack: curved, flattened and enlarged pro- and mesotarsal claws; pair of small spines on the prosternal anterior margin; pair of prominent processes on metasternal posterior margin. Females have a pair of oval perforations in the pronotal cuticle. Males and females are of similar size. The males (n = 3), 4.05-4.20 mm, and females (n = 4), 4.00-4.25 mm, also vary little in length. All specimens showed variability in the amount of plastron present on the elytra. Most individuals have the plastron lacking to some extent on the elytral intervals, with remnants mostly restricted to the lateral margins, striae, and punctures. This is presumably due to abrasion from the environment.

The single male specimen from Venezuela (Figs 4, 5) varied somewhat from the two males from Peru (Figs 1, 2) in the following manner: body slightly narrower; metaventral processes larger; genitalia (Fig. 5), in dorsal view, with penis thinner in apical ½ and with parameres thinner and not sinuate laterally. The differences are not marked, and with just one individual to compare with only two others, proposing it as a separate species of Amazonopsis  seems inadvisable.


Named for Therany Gonzales Ojeda of ACEER, Puerto Maldonado, Madre de Dios, Peru, the collector of the type series.


This species is currently known only from widely separated, single localities in southeastern Peru, southwestern Venezuela, and French Guiana (Fig. 6).


Quebrada Santo Rosario (Fig. 7), the type locality, is a small, second order tributary of the Río Tambopata which feeds the Río Madre de Dios, a major tributary of the Amazon River in Peru. The stream has a small watershed and flows from mostly undisturbed lowland forest at an elevation of 230 m. It was selected as a “control” site by the ACEER project because it was considered non-impacted by human activity. ACEER coordinator Therany Gonzales (in litt.) observed "It is a very clean stream because their [sic] head waters are into a primary forest between the road and the Inambari river that steel [sic] remains pretty well conserved … Collecting macroinvertebrates in this stream was very productive. We got a great diversity and abundance of macroinvertebrates." The specimens of Amazonopsis  were collected from artificial leaf pack samples containing the leaves of Inga edulis  , a leguminous tree common near streams in the region. Water quality data taken during the ACEER project are as follows: water temperature 25.2 °C, pH 5.13, dissolved oxygen 6.49 mg/L at 25 °C (79%), conductivity 5µS/cm, and turbidity 4 NTU ( Sweeney 2014). Observations from my field notes at the site on September 14 and 15, 2013, during which Bill Shepard and I were unsuccessful in collecting additional specimens of Amazonopsis  , were: water tannin-stained, current slow; bottom substrate of clay and mud with some cobbles; waterlogged wood, a few leaf packs, and root masses present. Quebrada Santo Rosario is intersected by the Interoceanic Highway near the San Juan community about 73 km southwest of Puerto Maldonado.

Crique Nouvelle France (Fig. 8) is a jungle stream in the watershed of the Maroni River, contained wholly within protected Parc Amazonien de Guyane near the community of Saül, in a remote area of central French Guiana. The stream is shallow and sand-bottomed with occasional areas of boulders which form small cascades. Logs, branches and leaf packs litter the channel, and the water is tannin-stained. The specimens were collected from leaf packs or other woody debris. Elevations at the two collection sites are approximately 150 m and 210 m. Water quality measurements taken at the time are as follows: water temperature 23.8 °C, pH 6.6, dissolved oxygen 7.05 mg/L (85.4%), conductivity 44.3 µS /cm, and turbidity 3.61 NTU (Clavier, in litt.).

The information for the Cerro de la Neblina site, a tributary Río Baria, was provided by collector Warren Steiner (in litt.) from his field notes: "small whitewater stream [where I] spent an hour collecting … in leafy side pools near flowing part of stream … ". The label data with the specimens states "small pool full of dead leaves" as well as an elevation of 140 m. In addition, Spangler (1990: 30) gave a description of the site as follows: "The small whitewater tributary … was about 1 m wide and 1 to 2 cm deep and was shaded by a dense canopy" … "a small, marshy, meandering whitewater rivulet with occasional shallow, leafy pools …”.

Associated taxa.

Aquatic byrrhoid beetles collected at the same localities as Amazonopsis theranyi  include: PERU: Gyrelmis brunnea  Hinton, 1940, G. longipes  Hinton, 1940, G. maculata  Hinton, 1940, Hintonelmis  Spangler, 1966 , Neoelmis  Musgrave, 1935, Pilielmis  Hinton, 1971, Portelmis  ( Elmidae  ); Psephenops  Grouvelle, 1898 ( Psephenidae  ). FRENCH GUIANA: Cylloepus  Erichson, 1847, Gyrelmis brunnea  , G. nubila  Hinton, 1940, G. spinata  Hinton, 1940, G. thoracica  Hinton, 1940, Heterelmis  Sharp, 1882, Hexacylloepus  Hinton, 1940, Hintonelmis perfecta  (Grouvelle, 1908), Macrelmis tereus  (Hinton, 1946), Neoelmis  , Pilielmis apama  Hinton, 1971, Phanocerus  Sharp, 1882 ( Elmidae  ); undescribed genus/species ( Protelmidae  ); Dryops  Oliver, 1791, Elmoparnus collinsae  Spangler & Steiner, 1983, Platyparnus bollowi  (Hinton, 1939), P. frater  (Hinton, 1939) ( Dryopidae  ); Lutrochus  Erichson, 1847 ( Lutrochidae  ). VENEZUELA: Gyrelmis  Hinton, 1940, Hexacylloepus  , Neoelmis  , Pilielmis  , Stegoelmis fera  Spangler, 1990, S. geayi  (Grouvelle, 1908), S. tuberosa  Spangler, 1990 ( Elmidae  ); new genus ( Protelmidae  ); Dryops  , Pelonomus  Erichson, 1847 ( Dryopidae  ). Note: Venezuelan records are cited from Spangler (1990: 30).