Araucnephia cearensis, Pessoa, Felipe Arley Costa, Ríos-Velásquez, Claudia María & Py-Daniel, Victor, 2012

Pessoa, Felipe Arley Costa, Ríos-Velásquez, Claudia María & Py-Daniel, Victor, 2012, A new species of Araucnephia (Diptera: Simuliidae) from the Northeast Region of Brazil, Zootaxa 3343, pp. 31-44 : 32-37

Araucnephia cearensis sp. nov. Pessoa, Rios-Velásquez & Py-Daniel

( Figures 1–69)

Adults: Large, length 2.8 mm (male), 3.5 mm (female). General body coloration blackish brown ( Figs 1, 16). Labellum wide ( Figs 10, 23). Clypeus prominent and higher than its width, with median longitudinal suture ( Figs 8, 17). Wing veins light brown; basal cell present ( Fig. 22); C with spinules and setae; Sc setose in female, bare in male; basal sector of R with hairs arranged in two or three rows, with spine-like setae present on distal one-third. Legs ( Figs 2–4) with light brown coxa with apical dark brown spot and black bristles; light brown femora with basal and apical dark brown spot; basal half of fore- and meso-tibia light brown, with apical halves dark brown; hind tibia light brown; tarsal segments dark brown. Calcipala wider than tall. Pedisulcus absent. Claws with small, triangular-shaped subbasal tooth ( Fig. 24).

Male: Antenna dark brown, with the apex thinner than the basal area, 0.66–0.68 mm (n = 2) in length; first flagellomere two times higher than its width, whereas other flagellomeres taper apically ( Fig. 5). Ratio of palpomeres 3: 4: 5 = 1.3: 1: 1.8 ( Fig. 10). Sensory vesicle of maxillary palpus rounded, covered with tubercles, occupying 2 / 3 of palpomere ( Fig. 11). Wing length = 2.5–2.7 mm; wing width = 1.06–1.32 mm. Scutum dark brown, velvety black posterolaterally, with wide dark brown band dorsomedially. Metanotum velvety black ( Figs 6–7). Katepisternum higher than wide, with complete sulcus. Abdomen dark brown with lateral black stripe on segments VI–VIII. Furcasternum expanded laterally of median branch with abrupt apical constriction ( Fig. 9). Ventral plate rounded. Median sclerite robust, curved, with bilobed plate ( Fig. 12). Gonostylus longer than gonocoxite, subconical, with submedian crest and two or three apical spurs ( Figs 13–15).

Female: Wing length = 2.9–3.06 mm; wing width = 1.16–1.3 mm. Frons, clypeus, antenna, maxillary palpus, and occiput black with grayish pollinosity. Frons width and height equal, with abundant pilosity; frontal angle = 90 °; frontocular triangle higher than wide, with long frontal suture ( Fig. 17). Clypeus prominent, higher than wide, with median longitudinal fissure ( Fig. 17). Antenna ( Figure 18) with grayish pubescence, 7.8–8 mm in length; scape and pedicel dark brown, flagellum pale brown, comprised of 9 tapering flagellomeres. Fronto-ocular triangle well developed, without infra-ocular suture ( Fig. 19) Maxillary palpomere (3: 4: 5) ratios = 1–1.23: 1: 1.28–1.3 ( Fig. 23); sensory organ about 1 / 3 of basal article length, with abundant tuberosities ( Fig. 25). Mandible denticulate on both sides with 38-39 + 1 + 21–24 teeth; maxilla with 12-13 + 1 + 19–20 teeth ( Fig. 25). Basal portion of cibarium smooth, without deep concavity, straight medially, with long sclerotized well-developed cornua and no teeth ( Fig. 26). Scutum and metanotum blackish. Scutum with 1 thin median and 1 + 1 wider submedian grayish vittae extending longitudinally from anterior to posterior; lateral and posterior margins and humeri blackish brown; prescutellar hairs black, recumbent; pleura blackish brown; scutellum black, with interspersed recumbent setae ( Figs 20–21). Katepisternum higher than wide. Halteres light brown. Legs similar to those of male. Abdomen blackish with grayish pollinosity; tergal plates velvety and darker than remainder of abdomen; pleura glabrous with grayish pollinosity; cerci with rounded margin; paraproct also rounded and slightly higher than wide ( Fig. 27); genital fork with thin, apically expanded median branch equal in length to lateral branches; ( Fig. 28); spermatheca subovoid, with duct, junction hyaline; spinules present ( Fig. 29).

Pupa: cocoon length 6.3 mm (n = 4, mean = 5.9–6.7); total pupa length = 6.1 mm (n = 4, mean = 5.7–6.2 mm); gill length = 1.9–2.86 mm (n = 4, mean = 2.65). Cocoon shapeless, not compact, with evident threads of soft woollike fiber, covering pupa up to gills ( Fig. 30). Head of pupa and body dark brown ( Fig. 31). Frontoclypeus and thorax without tubercles ( Figs 32–34); frontoclypeus with 3 + 3 small, simple, variably positioned epicraneal trichomes. Thorax with 6–8 single small trichomes per side. Gills short, less than 1 / 3 of pupal length, with 27–35 terminal branches organized as short basal trunk, with five short and one long primary branch carrying 15 secondary branches ( Fig. 35). Abdomen hard, sclerotized, with numerous small sternal platelets ( Fig. 36); onchotaxy typical of genus, with dorsal simple or bifid setae and ventral simple setae ( Figs 36–38). Sternites with basal spine comb; all sternites, except VII, with small rounded tubercles; sternites V to VII medially divided by longitudinal striate sternal membrane; sternite III with thin setae. Tergites V to IX with rows of large anterior spines; tergites III and IV with 4 + 4 small posterior hooks ( Figs 37, 39); tergite IX with two long terminal spines and looped trichomes ( Figs 40–41).

Larva: maximum length = 7.9–9 mm (n = 5). Color, light grayish brown ( Fig. 42). Head light brown with positive spots and very evident ornamentation, with darker area around ocular spot; labral apotome spots dark brown with basal transverse spot, one anteromedial and one posteromedial head spot, and negative anterolateral head spots ( Fig. 43). Cervical sclerite dark brown, wide, elliptical, and free of membrane ( Fig. 44). Postgenal cleft subtriangular and wider basally. Ratio of hypostomium/hypostomial bridge/postgenal cleft = 1: 0.7–0.97: 0.8–0.97 ( Fig. 45). Hypostomium with one prominent median tooth, three less prominent and one reduced sublateral teeth, one lateral tooth, and three paralateral teeth ( Figs 48–49), and 5–9 lateral serrations per side. Hypostomium with one or two irregular rows of 6–8 long, lateral setae per side, with 3 – 3 short setae posteriorly near hypostomal groove ( Fig. 49). Antennae shorter than stem of labral fan ( Fig. 43). Antennal articles sclerotized; ratio of antennal articles I–III = 1: 1.6–2.3: 2.7–3.08 ( Figs 50–51). Basal portion of second segment pale, with other parts dark. Mandible ( Figs 52–54) with two outer teeth, one apical tooth, and three pre-apical teeth; third pre-apical tooth longer than first and first longer than second; internal teeth arranged in several rows; 8–12 marginal teeth, where first is longest; two accessory teeth on external side sometimes anterior to first or at same level as median internal; presence of small lateromandibular process (LMP) ( Fig. 53). Labral fan with 40–42 rays ( Fig. 55); according to Palmer and Craig (2000) microtrichial classification, comb of rays basally weak complex type ( Figs 59, 60, 63–65), standard type apically ( Figs 56 –58, 61– 62), while apex of microtrichiae large and strong, larger than others, resembling harpoon ( Figs 58, 61– 62). Second very small row of microtrichiae present ( Figs 61–65). Labral fan ( Fig. 60), with poorly developed spine basally; labral fan base/apex ratio = 1: 3–4.3; scale fan with 6–7 rays. Labral sclerite with small teeth. Prothoracic proleg sclerite enlarged medially, with ungrouped setae; comb with 15–17 teeth ( Figs 66–67). Anal sclerite X-shaped ( Fig. 68), with single trichomes and abundant scales bearing 4–8 branches; presence of uncommon taxonomically median accessory sclerite between posterior arms of the anal sclerite, projecting among the row of hooks ( Fig. 69). Anal ring with 124–129 rows, each with 19–25 hooks. Anal gill with three long unbranched lobes ( Fig. 46), Ventral tubercles small ( Fig. 47).

Etymology. The species name cearensis refers to the state of type locality, Ceará State, Brazil.

Bionomics. Most of the aquatic forms were collected from rocks while a few were found among deciduous leaves in poorly lit riffles. The stream at the type locality was mostly bedrock bottomed and its flow was reduced during the dry season (width = 0.5 m, depth = 5–20 cm). We sampled the area several times during the dry season and we collected very few larvae, although the small stream had flowing water at all sampling points. In March 2011, we collected more individuals during the rainy season so population size of this species appears to be strongly associated with periods of cooler, wetter weather when the flow, velocity, and turbidity of the stream are increased. We did not find this species in other tributaries of the Gavião River near this small stream, which seemingly had the same physical characteristics. Other Araucnephia species are anthropophilic (Coscarón & Coscarón- Arias 2002, Wygodzinsky & Coscarón 1973 b), but none of the collectors ( FACP and CMRV) felt any black fly bites in the area.

Type locality: Specimens were collected from a small tributary of the Gavião River, near Erundina Hotel, Balneário Cascatinha Road, Mount Maranguape, approximately 750 masl, Maranguape Municipality, Ceará State, 3 ° 53 ′ 27 "S, 3441 ′08"W.

Taxonomic comments: Wygodzinsky and Coscarón (1973) created the genus Araucnephia based upon characters of the female genitalia and mandibles (toothed), pupal trichome patterns, and antenna length and hypostomium structure of the larva. Coscarón and Coscarón-Arias (2002) maintained the genus when they described a new species, A. iberaensis , from Argentina, while in 2007 (Coscarón and Coscarón-Arias) they provided keys for the identification of the species. In 2010, Shelley et al. proposed the synonymy of Araucnephia and Araucnephioides Wygodzinsky & Coscarón with Lutzsimulium d'Andretta Jr & Vulcano , based on the presence of looped thoracic trichomes. Such trichomes are present in A. iberaensis but not in other members of the genus. Thus, the taxonomic limits of Araucnephia and Araucnephioides remain controversial. However, morphological-based phylogenies that consider multiple characters do not group Lutzsimulium , Araucnephia , and Araucnephioides in a single monophyletic clade (Gil-Azevedo & Maia Herzog (2007), Gil-Azevedo 2010). Adler and Crosskey (2012) recognized the genus Araucnephia in their latest World species checklist, so we have also decided to recognize the genus as valid.

The new species follows the general pattern of Araucnephia as defined by Wygodzinsky and Coscarón (1973), Py-Daniel (1990) and Coscarón and Coscarón-Arias (2002). The pupae can be separated from other Araucnephia pupae based on the number of gills ( A. montana has 14, A. iberaensis has 9, and A. cearensis sp. nov. has 25–35). Another evident autapomorphy of the pupae of A. cearensis sp. nov. is its fully enclosed pupal cocoon, which is shapeless and completely obscures all internal pupal structures. Pupae from the other two described species in the genus Araucnephia have exposed gills. As with A. montana pupae, the frontoclypeus and thorax of A. cearensis sp. nov. lack the platelets present in A. iberaensis pupae. The larva of A. cearensis can be separated from A. montana and A. iberaensis based on its median accessory anal sclerite, which is not present in the other two species in the genus. The lateromandibular process found in A. cearensis sp. nov. is similar to that found in A. iberaensis ( Fig. 70), which was not mentioned in the original description although it was drawn partially (Coscarón and Coscarón- Arias, 2002; fig. G, page 86). Slide-mounted mandibles of A. montana larvae lack this structure. Palmer and Craig (2000) correlated the microtrichiae types in black fly labral fans with the type of stream/river they inhabit. Two types of labral fan arrangements were recorded in this new species. These two forms are also present in A. montana , whereas A. iberaensis has only one microtrichial arrangement, i.e., a weak complex form. A possible explanation for the presence of two microtrichiae patterns in both A. montana and A. cearensis sp. nov. species is disruptive selection. Both Araucnephia montana and A. cearensis sp. nov. larvae are found in mountainous regions where the water levels and flow velocities may vary dramatically between the dry and wet seasons. Thus, it is possible that the maintenance of these two very different arrangements within a single species could be a result of different filter-feeding selection pressures, which fluctuate seasonally.

The type locality of A. cearensis sp. nov., i.e., Mount Maranguape, is part of a mountain range that comprises the Brazilian shield. This geological formation is composed of crystalline rocks from the Inferior and Medium Precambrian, which are much older than the Andean mountains (that arose during the Tertiary period). Coscarón and Coscarón-Arias (1995) initially proposed that Araucnephia might be restricted to southern South America because of their high degree of endemism and the strong biogeographic barrier separating the Chilean and the Argentinean Andean regions from the Eastern lowlands. However, they revised this proposal when they described A. iberaensis in the Argentinean lowland ( Coscarón & Coscarón-Arias 2002). The results presented here extend the northern range of the genus Araucnephia beyond an ancient mountain range that arose prior to the Andes. These data agree better with the hypothesis that Araucnephia are derived from a common, widespread Gondwanan ancestor ( Coscarón & Coscarón-Árias, 1995).