Neblinagena mira, Čiampor, Fedor, Čiamporová-Zaťovičová, Zuzana & Kodada, Ján, 2017

Čiampor, Fedor, Čiamporová-Zaťovičová, Zuzana & Kodada, Ján, 2017, A new species of Neblinagena Spangler from Kukenán tepui and DNA barcoding of Neblinagena and related genera (Coleoptera: Elmidae), Zootaxa 4286 (2), pp. 176-186 : 178-184

Neblinagena mira sp. n.

Type locality. Small stream at the foothills of the Kukenán tepui with cascades and riffles, large boulders, stones and gravel, flowing through savannah, surrounded by remnants of gallery forest ( Fig. 32 ).

Type material: holotype ♂ ( NMW): ” Venezuela, Estado Bolivar, 29.XI.2015, Kukenán River, below Kukenán tepui , 5°09.359'N 60°49.508'W, 1631 m a.s.l., T. Derka & D. Gruľa lgt.", paratypes 7 ♂, 3 ♀ ( CCB, CKB, MIZA): with the same locality data as holotype.

Description. Body elongate ( Fig. 1 ), CL: males 5.64–6.14 mm, females 5.90–6.01 mm, 3–3.2 times as long as wide (CL/EW), dorsum moderately convex, surface hairy. Body dark brown to black; scape, pedicel, basal parts of femora paler; ventral side lighter due to yellowish pubescence.

Head ( Figs 5, 7 ) partly retractable into thorax, densely setose, HW: males 1.06–1.09 mm, females 1.04–1.09 mm, ID: males 0.62–0.66 mm, females 0.60–0.63 mm. Labrum ( Fig. 5 ) with long setae, short, anterior margin shallowly emarginate in the middle, lateral angles rounded; clypeus about as long as labrum; frontoclypeal suture scarcely visible. Eyes well developed, protruding beyond outline of head, suboval in lateral view; setae around eyes short; frons with longitudinal depressions near eyes. Maxilla ( Fig. 9 ): cardo and stipes densely setose; lacinia slightly elongated, distally with rows of dense, apically curved setae; galea two-segmented; maxillary palpus foursegmented, terminal segment longest and widest, truncate apically, segments 2–4 densely setose. Mandibles as in Fig. 8 . Labium ( Fig. 10 ): mentum transverse with very long setae, anterior margin with dense shorter setae; palpus three-segmented, distinctly larger and longer than maxillary palpus, terminal segment robust, truncate apically, with apical sensory field. Antennae ( Fig. 6 ) eleven segmented, densely setose, scape long, curved, pedicel short, segments 3–11 forming elongated club, longer than scape and pedicel combined.

Thorax. Pronotum ( Fig. 11 ) widest at base then sinuately narrowing anteriorly, anterior margin widely arcuate, PW: males 1.66–1.81 mm, females 1.63–1.74 mm, PL: males 1.22–1.35 mm, females 1.30–1.31 mm; base broadly sinuate on each side and narrowly so in front of scutellum; posterolateral angles acute, slightly protruding, depressed; middle of base with 2 short prescutellar oblique carinae; each carina with distinct lateral depression; disc convex, with median groove from base to ca. anterior ¼, less depressed in the middle; transverse curved grooves in anterior ¼; lateral margins narrowly explanate; anterior angles very indistinctly protruding. Hypomeron sinuate, widest at base. Prosternal process ( Fig. 12 ) less than 1.2 times as long as wide, constricted at base, obliquely widened in middle, then narrowing toward rounded apex. Surface of prosternum densely setose. Mesoventrite ( Fig. 16 ) short and wide, with deep rhomboid depression for reception of prosternal process. Metaventrite ( Fig. 16 ) with sides of disc raised in posterior ¾, discrimen fine, depressed from the anterior ¼ to posterior margin. Elytra ( Figs 1 , 14 ) with 10 rows of minute punctures, sides subparallel in anterior 0.55, then tapering toward feebly produced apices, 2.33–2.52 times as long as wide; EL: males 4.42–4.79 mm, females 4.60–4.70 mm; EW: males 1.88–2.05 mm, females 1.86–2.00 mm; disc without tubercles or accessory rows ( Fig. 15 ); epipleuron narrow, setose. Scutellum flat, obovate. Legs ( Fig. 13 ) moderately long, femora flattened, mesofemora longest, pro- and mesofemora dorsally with elongated setae; tibiae not flattened, protibiae longest; tarsi setose, terminal tarsomere longest but shorter than combined length of tarsomeres 1–4, claws well developed, pointed; metacoxae transverse, laterally distinctly narrowed.

Abdomen ( Fig. 17 ) setose; intercoxal process of first ventrite triangular, carinae of ventrite 1 behind coxae weak or absent; ventrites transverse, with slightly convex lateral sides; ventrite 5 about as long as ventrites 3 and 4 combined, narrowed distally. Aedeagus ( Figs 18–20 ) elongate, fibula absent, corona membranous; parameres ca. ¾ as long as median lobe, wide in basal ¼, distal ¾ extremely narrow (lateral view), apices subacute; median lobe slender with narrowed rounded apex; phallobase short with basal apophyse. Ovipositor very similar to that of N. prima .

Distribution. N. mira is known only from the type locality ( Fig. 32 ) next to the Kukenán tepui in the Bolivar state ( Fig. 33 ).

Differential diagnosis. N. mira can be easily distinguished from the two known Neblinagena species by its pointed elytral apices, constricted prosternal process, short setae around eyes and by shape of male genitalia.

Etymology. The new species was named “ mira ”, which means in Latin “strange, remarkable, amazing”. The name underlines the fact, that N. mira is genetically very distant from N. doylei , and differs morphologically from N. prima figured in Spangler, 1985 and also in Maier 2013. On the other hand, the pronotum of N. mira and some other features resemble that of the original description of N. prima (the type species of the genus). Unfortunately, the DNA data for N. prima are not available, so we cannot be certain whether N. mira belongs to the genus Neblinagena or represents morphologically similar, but genetically distinct genus.

Description of larva. Length ca. 10.7 mm, greatest width ca. 1.70 mm. Dorsal side dark grey-brown, ventral side slightly paler, legs brown. Body ( Figs 2, 3, 4 , 21 ) cylindrical in cross section, ventral side slightly flattened. Spiracles present laterally on mesotergum and abdominal segments I–VIII; surface densely covered by flattened or adpressed scales of various shape.

Head ( Figs 22, 23 ) prognathous, partially retracted into prothorax. Cuticle covered by scales intermixed with few long semierect setae. Five stemmata separated in two groups on each side of head ( Fig. 24 ). Antennae short, three segmented; scape widest with ring of apical scales; pedicel elongate, glabrous; flagellum and sensorium were unfortunately absent in all specimens available in this study. Epicranial suture and frontoclypeal suture hardly visible. Clypeus narrow, labrum broader than long with sides converging, anterior portion covered with yellowish setae. Maxilla ( Figs 23, 25 ) slender, subparallel, slightly curved; maxillary palpus four-segmented, last segment shortest. Labium ( Fig. 23 ) about 1.5 times longer than wide, parallel-sided, slightly narrowed anteriorly; labial palpi very short. Maxillae and labium with sparse scales, apically and subapically with pectinate setae ( Fig. 25 ).

Thorax. Protergum widest in basal half ( Figs 2 , 21 ), convex, disc with pair of admedian carinae reaching protergal margins, pair of sublateral carinae interrupted in about middle and pair of lateral carinae extending from base to about middle of protergum, carinae with erect scales. Lateral margins with scales, distal margin, as on all other segments except the last, with longer recumbent flattened setae. Mesotergum and metatergum shorter with three setigerous carinae on each side as on protergum. Sclerites of thorax as in Figs 26–27 . Forelegs shortest, mid- and hindlegs longer, similar in shape. Coxae long and robust, transverse; trochanter about half as long as coxa, subtriangular; femur slender, basally oblique; tibia narrowing toward tarsungulus.

Abdomen ( Figs 21, 28 ) with nine sparsely setigerous segments, tergites I–VIII with three shortened setigerous carinae on each side, ninth tergite with mesal carina narrow, posterior margins with dense elongate scales; lateral parts bearing biforous spiracles ( Fig. 28 ). Sternites I–VIII similar in shape, wider than long, punctate, pleurites I–VIII elongate rectangular, pleurites VII narrowed posteriad, triangular, pleurites VIII fused with sternites. Abdominal segment IX narrowed toward rounded apex; ventral operculum ( Figs 29, 30 ) suboval, concave, with apical opercular claws well developed.

Discussion

The Guiana Highlands, with its tropical lowlands and numerous isolated flat-topped tepuis reaching up to 3000 m a.s.l., is known for its remarkable biodiversity and high level of endemism (e.g. Derka et al. 2012, Nieto & Derka 2011). The streams flowing from the tepuis also harbour endemic insects ( Derka et al. 2015, Kodada et al. 2012, Čiampor & Kodada 1999), including a few genera of Elmidae (e.g. Roraima, Jolyelmis ). The genus Neblinagena was described from the Cerro de la Neblina tepui. The type series of N. prima (type species of the genus) included specimens from wide altitudinal interval: 770–2100 m a.s.l. (see Spangler 1985), which is not very common within South American Elmidae .

Here we described the new species from another table mountain—Kukenán tepui, and according to the molecular data from larval specimens we confirmed the occurence of Neblinagena also in the Auyán tepui. Neblinagena mira sp. n. is morphologically similar to N. prima and N. doylei , but genetically it is more related to representatives of the genus Roraima. The distinct genetic distance of N. mira from N. doylei suggests that they might even represent different genera. Unfortunately, molecular data on N. prima are not available. Thus for the moment we cannot solve the taxonomic question, whether N. doylei , usually distributed in lower altitudes, represents a different genus, or it belongs to Neblinagena and that N. mira sp. n. should be classified in a new genus. Due to lack of important molecular data and due to the morphological similarity, we decided to describe the new species in the genus Neblinagena . Nevertheless, the molecular data proved invaluable in distinguishing species and elucidating the biological diversity more precisely. We added to the knowledge of the distribution and diversity in the Guiana Highlands, even from one locality where only larvae were available. We also showed that morphologically similar species from the same area can be phylogenetically well separated, and can form distinct and well isolated lineages with differences similar to those between morphologically well delimited genera.

Figures

FIGURES 32 – 33. 32) type locality of Neblinagena mira sp. n., Kukenán River, below Kukenán tepui, 1631 m a. s. l.; 33) distribution map of the genus Neblinagena: green dots— N. prima, red dots— N. doylei, yellow dot— N. mira sp. n., blue dot—larvae of Neblinagena sp. from Auyán tepui.

FIGURES 1 – 4. Neblinagena mira sp. n.: 1) habitus, 2) larva dorsal view, 3) larva ventral view, 4) larva lateral view. Scale bar: 1 mm.

FIGURES 5 – 17. SEM photos of Neblinagena mira sp. n. imago: 5) head dorsal view, 6) detail of left antenna and eye with surrounding hairs, 7) head ventral view, 8) left mandibula dorsal view, 9) left maxilla dorsal view, 10) labium, 11) pronotum, 12) prosternum, 13) mid leg, 14) right elytron, 15) detail of anterior part of right elytron, 16) meso and metaventrite, 17) abdominal ventrites.

FIGURES 18 – 20. aedeagus of Neblinagena mira sp. n.: 18) ventral view, 19) dorsal view, 20) lateral view. Scale bar: 0.1 mm.

FIGURES 21 – 30. SEM photos of larva of Neblinagena mira sp. n.: 21) habitus dorsal view, 22) head dorsal view, 23) head ventral view, 24) right stemmata, 25) antenna and distal part of maxilla, 26) head and thorax latero-ventral view, 27) thorax ventral view, 28) abdominal segments I – III, 29) ventral operculum lateral view, 30) abdominal segments VIII – IX and ventral operculum ventral view.