Gyrinus (Oreogyrinus) venezolensis Ochs, 1953

Gustafson, Grey T. & Short, Andrew E. Z., 2017, Review of the whirligig beetle genus Gyrinus of Venezuela (Coleoptera: Gyrinidae), Acta Entomologica Musei Nationalis Pragae 57 (2), pp. 479-520 : 505-508

Gyrinus (Oreogyrinus) venezolensis Ochs, 1953

( Figs 33–34 , 39 , 41 , 43–44 , 48 , 58 , 62–63, 72, 80)

Gyrinus (Oreogyrinus) venezolensis Ochs, 1953: 185 (original description).

Type locality. ‘ Venezuela Mérida’.

Type material examined. PARATYPES (4 spec. SMF): ‘J [white label, typed black ink]’ ‘ Merida [white label, typed black ink]’ ‘ Venezuela / Briceno [white label, typed black ink]’ ‘coll. / G.Ochs [white label, typed black ink]’ ‘Para- / typoid / SMF / C 9065 [red label, black border, typed black ink]’ ‘Senckenberg- / Museum / Frankfurt / Main [white label, typed black ink]’ ‘ Gyrinus / venezolensis / Paratype Ochs / J 1942 [white label, handwritten black ink, handwriting is Ochs’]’ ‘ venezolensis Ochs [white label, black border, handwritten black ink, handwriting is Ochs’]’. Card mounted ♀, same locality as previous except ‘Mus. Berlin don. 1942 [white label, black border, typed black ink] ’; paratype SMFC 9066 , andwithouthandwritten Ochsdet labels. Cardmounted J and ♀ ( Fig. 73 ), ‘ DR Moritz / 1858 / Venezuela [beige label, typed black ink]’, paratypes SMFC 9068 , SMFC 9069 .

Other material examined. VENEZUELA: MÉRIDA: Rt. 4, 27 km N. of Mérida , 20.ii.1976, leg. CM. & O.S.Flint Jr. (20 spec. USNM) ; Bailadores , roadside stream, 8°14’27.94”N, 71°48’57.37”W, 15.i.2006, leg. A. E.Z. Short, mud / gravel stream, AS-06-032, SM0828873–SM0828878 (6 spec. SEMC) ; Cascada de Bailadores , 8°14.393’N, 71°48.672’W, 1862 m, 18.vii.2009, leg. Sites, stream, VZ09-0718-02S / L-1092, SEMC0879873 – SEMC0879874 (2 spec. SEMC) ; ca. 4 km E Jaji , 8°34.574’N, 71°18.806’W, 1830 m, 16.i.2006, leg. A. E.Z. Short, Lagoon in pasture, AS-06-035, SM0827433–SM0827451, SM0827453–SM0827470, SM0827472–SM0827486 (52 spec. SEMC, MIZA, MALUZ) .

Diagnosis. Body form ( Fig. 33 ) oval, in lateral view strongly convex; pronotal disc with transverse crease strongly impressed, laterally with sparse wrinkles ( Fig. 39 ); elytral disc of female with intervals I–IV non-reticulate inbasal half ( Fig. 43 ), V–X strongly reticulate ( Fig. 44 ), XI non-reticulate; female elytral striae VI–IX sulcate ( Fig. 41 ); elytral lateral margin weakly interrupted before apex ( Fig. 41 ); metanepisternal ostiole present; aedeagus ( Fig. 48 ) with median lobe strongly parallel sided for 2/3 length, apex broad, weakly triangular or rounded; parameres truncate apically.

Gyrinus venezolensis ismostsimilar to G. vinolentus sp. nov. but canbe distinguished from it by being more evenly oval in dorsal habitus, having a less wrinkled pronotum (c.f. Figs 39 and 40 ), and the elytral lateral margin weakly interrupted in its apical 1/5 by a swelling ( Fig. 41 ), as opposed to being strongly interrupted by a relatively large swelling ( Fig. 42 ). Females of G. venezolensis can further be distinguishedfrom G. vinolentus sp. nov. byhaving somewhat less reticulate elytra, with reticulation only being regularly present on intervals V–X, as opposed to G. vinolentus sp. nov in which intervals IV–X are normally reticulate (at least in basal half of intervals IV–V). The male aedeagus is the most reliable way to separate the two species, as in G. venezolensis the parameres are apically truncate, and the median lobe is strongly parallel sided in its apical 2/3, with a broad apex ( Fig. 48 ), compared to G. vinolentus sp. nov. which has rounded apices to the parameres and the median lobe strongly constricted in its apical 1/3, with a rounded apex ( Fig. 49 ). The female gonocoxae also differ strongly between the two species, being more elongate and less curved in G. venezolensis ( Fig. 58 ) compared to the relatively shorter and more strongly curved gonocoxae of G. vinolentus sp. nov. ( Fig. 59 ).

Redescription. Size. Female length = 5.0– 5.5 mm, width = 3.0– 3.5 mm, male length = 4.5–5.0 mm, width = 2.5–3.0 mm. Habitus. Body form evenly oval, attenuated anteriorly and posteriorly, widest point just posteriad of humeral region; in lateral view dorsoventrally strongly convex, greatest convexity posterior to scutellar region, evenly depressed anteriorly and posteriorly.

Coloration ( Figs 33–34 ). Dorsally, head, pronotum, elytra black, with blue reflections; laterally reflections bronzy yellow and green, especially in females whose elytral lateral reticulation appears strongly bronzy green. Venter overall darkly colored; mouthparts, ventral surfaceof antennalpedicel, hypomeron, elytral epipleuron, mesoventrite medially, mesocoxae, and ultimate abdominal ventrite lighter in color – reddish brown to darker orange yellow; legs yellow in color; remainder of venter dark brown to black.

Sculptureand structure. Pronotum of bothsexes with broad riffled lateralmargins ( Fig. 39 ); pronotal disc laterally weakly wrinkled ( Fig. 39 ), wrinkles present anteriorly and associated with pronotal transverse impressed line, wrinkles also present posteriorly near posterior margin of pronotum. Female elytra ( Figs 33 and 41 ) with striae I–IV non-sulcate, elytral striae V–IX strongly sulcate in basal 2/3 of elytron, stria X non-sulcate, stria XI strictly marginal. Female elytral disc with intervals I–IV normally non-reticulate ( Fig. 43 ), always basally free of reticulation; interval Valways with reticulation present at least apically or in lateral half near stria V; intervals VI–X completely reticulate ( Fig. 44 ), reticulation with impressed dense meshes, composed of scale-like sculpticells; interval XI free of reticulation. Male elytra ( Fig. 34 ) with striae I–IV non-sulcate; V–VII weakly sulcate after humeral region for brief extant; VIII–IX sulcate in humeral region, ending before apical 1/3 of elytron; stria X non-sulcate; stria XI strictly marginal. Male elytral disc with intervals I–XI without reticulation. Elytra of both sexes withlateralmargins weakly interrupted interrupted inapical 1 /5 by minor swelling; elytral apex truncate to weakly rounded. Metanepisternal ostiole very small.

Malegenitalia ( Fig. 48 ).Aedeagus withmedianlobe narrow, shorter than parameres, weakly attenuated after basal 1/3, strongly parallel sided in apical 2/3, apex broad, weakly triangular; in lateral view median lobe thick, strongly dorsally curved; parameres with apex strongly truncate. Female genitalia ( Fig. 58 ). Gonocoxae elongate, mostly straight with curved lateral margins, apices relatively truncate, weakly emarginate laterally, with lateral angle distinct, left gonocoxal apex less emarginate laterally than right.

Variability. There isvariability in the extent of the female elytral reticulation. Few specimens examined had the reticulation absent on interval Vbasally, with the reticulation present only apically and onthe lateral half of the interval near stria V. Afew other specimens hadinterval IV with reticulation in its apical half. However, it was most common for the species to have elytral interval IV free of reticulation in its basal half, having reticulation at most apically, and with interval V completely reticulate.

Habitat. This species has been collected from both streams and lagoons (Figs 62–63).

Distribution. Known only from the southern Venezuelan Andes in Mérida ( Fig. 72 ).

Discussion. While currently only known from Venezuela, given its distribution in the far southern Venezuelan Andes ( Fig. 72 ), this species may also be found inthe Andes of northern Colombia.

Figures

Figs 29–33. Dorsal and lateral view of the aedeagus of Neogyrinus species, not to scale. 29 – G. ovatus Aubé, 1838. 30 – G. sabanensis sp. nov. 31 – G. guianus Ochs, 1935. 32 – G. rozei Ochs, 1953.

Figs 33–38.Dorsal habitus of Oreogyrinus species, scale bar = 1 mm. 33 – Gyrinus venezolensis Ochs, 1953, female. 34 – G. venezolensis, male. 35 – G. vinolentus sp. nov. female. 36 – G. vinolentus, male. 37 – G. iridinus sp. nov., female paratype. 38 – G. iridinus, male holotype.

Figs 39–40. SEM images of the pronotum showing sculpturing of wrinkles and riffles of the lateral margins, arrows indicate pronotal transverse crease. 39 – Gyrinus venezolensis Ochs, 1953. 40 – G. vinolentus sp. nov.

Figs 41–42. SEM images of the elytron of Oreogyrinus species, scale bars = 1mm, arrows indicate the pre-apical swelling interrupting the elytral lateral margin. 41 – Gyrinus venezolensis Ochs, 1953. 42 – G. vinolentus sp. nov.

Figs 43–46. SEM images of elytral interval reticulation and strial punctures. 43–44 – Gyrinus venezolensis Ochs, 1953. 43 – intervals II and III, striae I–III. 44 – intervals IX and X, striae VIII–X. 45–46 – G. vinolentus sp. nov. 45 – intervals II and III, striae I–III. 46 – intervals IX and X, striae VIII–X.

Figs 47–50. Dorsal and lateral view of the aedeagus of Oreogyrinus species, not to scale. 47 – Gyrinus colombicus Régimbart, 1883, syntype (MNHN). 48 – G. venezolensis Ochs, 1953. 49 – G. vinolentus sp. nov. 50 – G. iridinus sp. nov.

Figs 51–59. Ventral view of gonocoxae of Venezuelan Gyrinus species, not to scale. 51–56 – Neogyrinus species. 51 – G. gibbus Aubé, 1838 from Caracas valley, Venezuela (FMNH). 52 – G. gibbus from Amazonian Venezuela: Amazonas stream along Rio Sipapo (KBMC). 53 – G. ovatus Aubé, 1838 from Venezuela: Falcón: W. Curimagua, Blackwater Lagoon.54 – G. guianus Ochs, 1935 from Amazonian Venezuela:Amazonas:river near Orinoco /Sipapo confluence (KBMC). 55 – G. rozei Ochs, 1953. 56 – G. sabanensis sp. nov. 57–59 – Oreogyrinus species: 57 – G. iridinus sp. nov. 58 – G. venezolensis Ochs, 1953. 59 – G. vinolentus sp. nov.

Figs 72–75. Distribution maps of Gyrinus species within Venezuela.