Revision of the genus Niphta (Diptera, Thaumaleidae) Theischinger of South America, with descriptions of nine new species and a new immature morphotype

Abstract The Niphta Theischinger fauna of South America is revised to include 11 species, nine of which are described as new to science (N.acus Pivar, sp. nov., N.bifurcata Pivar & Moulton, sp. nov., N.bispinosa Pivar & Sinclair, sp. nov., N.brunnea Pivar, sp. nov., N.courtneyi Pivar, sp. nov., N.daniellae Pivar, sp. nov., N.downesi Pivar, sp. nov., N.eurydactyla Pivar, sp. nov., N.mapuche Pivar, sp. nov.). The genus Niphta is redefined, both previously described Chilean species are redescribed, N.halteralis (Edwards) and N.nudipennis (Edwards), and females are described or redescribed where possible. The first descriptions of the immature stages of South American Niphta are provided, which represent a new larval morphotype in Thaumaleidae, as larvae and pupae possess ventral adhesive structures. Furthermore, these larvae were collected from vegetation rather than rocky substrates. Illustrations and micrographs are provided for all species, and scanning electron microscopy images are included for select immatures. A key to species, distribution maps, and discussions regarding phylogenetic affinities and habitat are also included.


Introduction
Thaumaleidae, or madicolous midges, consist of nearly 200 species classified in seven genera. They have no known medical or economic importance to humans, and are considerably less studied than their presumptive sister family, Simuliidae (black flies) (Moulton 2000;Bertone et al. 2008;Wiegmann et al. 2011;Borkent 2012;Kutty et al. 2018). Adults are commonly collected from rock-face seepages, margins of waterfalls and splash zones of cascading streams (Sinclair 2000;Pivar et al. 2018a, b;Pivar et al. 2020). Thaumaleid larvae are restricted to madicolous habitats, or substrates with a thin film of water flowing over them (Mackie 2004;Shimabukuro and Trivinho-Strixino 2018). Until this study, larvae were thought to be limited to rocky substrates. South America has eight described species of Thaumaleidae in three genera prior to this study, known from only three countries: Austrothaumalea Tonnoir (five species, Chile and Argentina), Neothaumalea Pivar, Moulton and Sinclair (one species, Brazil) and Niphta Theischinger (two species, Chile). Edwards (1930) was the first to describe thaumaleids from South America, including three species of Austrothaumalea and two species of Niphta. Schmid (1970) later described an additional species of Austrothaumalea. The first record of the family from Brazil was published by Pivar et al. (2018b), where they described the new genus and species, Neothaumalea atlantica Pivar & Pinho. Pivar et al. (2020) described an additional species of Austrothaumalea, synonymised Oterere McLellan with Austrothaumalea and provided a key to South American genera and species of Austrothaumalea. In addition to the described species above, Röder (1886) noted an undescribed species from the Ecuadorian Andes, though this record remains unverified by the authors despite attempts to locate the specimen.
The focus of this study is the South American Niphta, a small genus with two described species in Chile (Edwards 1930) and three in Australia (Theischinger 1986). The original descriptions by Edwards were brief and illustrations rudimentary, both severely lacking in detail. Discussions regarding relationships and keys were lacking, and immature stages unknown. Herein, Niphta is redefined, nine new species are described, Edwards' species are redescribed and females are described or redescribed for all available species. Genitalic illustrations are included for all species and available sexes. Additionally, immature stages of South American Niphta are described for the first time. Distribution maps, keys to species (see Pivar et al. 2020 for key to genera), and discussions regarding phylogenetic affinities, faunal patterns and habitat are also provided.

Materials and methods
Efforts were made to recollect fresh material from as near as possible to the perceived type localities. Adults were collected using an aerial net to sweep above the madicolous substrate and adjacent riparian vegetation. Sweeping for adults should be attempted first, if possible, to avoid having to sweep less accessible areas if they try to escape when searching for larvae. Immatures were collected by using forceps to pull them off the substrate, or by pouring water over the substrate and flushing immatures into a white pan (Sinclair and Saigusa 2002). In addition to examining rocks, vegetation (including leaves, stems, branches, etc.) in the splash zone should be carefully examined for larvae and pupae. This also includes inspecting any debris collected while sweep netting for adults, as it may contain immatures. Once collected, all life stages were placed directly into 75% non-denatured ethanol for morphological studies or 95% non-denatured ethanol for molecular studies.
Adult genitalia were cleared with hot 85% lactic acid. Representative adults and immatures were also cleared with the GeneJET Genomic DNA Purification Kit #K0722 (ThermoScientific, Waltham, MA) to maintain important membranous and lightly sclerotised structures, and to extract DNA for subsequent molecular study. The GeneJET lysate preparation protocol was followed and cleared voucher specimens were stored in 70% non-denatured ethanol. Positive identifications of females and immatures were made by comparing their DNA sequences to those of identified males. Specimens identified through molecular means are denoted by an asterisk (*) in the Type material and Additional material examined sections. Pinned specimens were dried using Brown's (1993) hexamethyldisilazane (HMDS) method. Cleared terminalia were preserved in glycerine-filled microvials pinned beneath the specimen.
Specimens were viewed using a Meiji Techno RZ stereomicroscope mounted with a Progres Gryphax Naos 22-megapixel camera (Jenoptik, Jena, Germany) and aided by iSolution Lite x64 software (Focus Precision Industries, Victoria, MN, USA) to take light micrographs of pinned adults and immatures in alcohol. Image stacks were created using Helicon Focus 6.7.1 (HeliconSoft, Roseau Valley, Dominica). Cleared terminalia and larval head capsules in glycerine were viewed with an Olympus BH-2 compound microscope equipped with DIC and images were taken following the same methods as above. Line drawings were first traced from stacked micrograph images captured using the compound microscope, structures were re-evaluated by closely reexamining specimens (as stacking failed to clearly differentiate critical internal structures), then line drawings were inked and digitised for publication. The left gonocoxite and gonostylus were intentionally omitted for male Niphta nudipennis group species to allow for clearer visualisation of remaining genitalic characters.
Samples were prepared for scanning electron microscopy by transferring specimens from 95% non-denatured ethanol into a 12 mm × 30 μm microporous specimen capsule (Electron Microscopy Services, Hatfield, PA). Capsules were then subjected to the following HMDS dehydration series, each step lasting 20 minutes: 100% ethanol, 1:1 ethanol to HMDS, 1:75 ethanol to HMDS, then two steps of 100% HMDS. Dried specimens were mounted on carbon tape affixed to 45°/90° aluminium stubs and sputter-coated with gold for 10 sec at 20 μA in a SPI-Module Sputter Coater (West Chester, PA). Specimens were viewed with a Hitachi TM3030 electron microscope (Tokyo, Japan) at a voltage of 15 kV.
Terms used for adult structures follow Cumming and Wood (2017). Homology of the male terminalia follows Sinclair (1992). Terms used for larval and pupal structures follow those of Courtney et al. (2000) and Borkent (2012), respectively. The number-ing system for larval head capsule setae and sensory pits follows Sinclair and Stuckenberg (1995). Distribution maps were created with SimpleMappr (Shorthouse 2010).
Label data for primary types are presented exactly as they appear. Data are listed from the top downward on the staging pin, with data from each label enclosed in quotation marks; lines are delimited by a forward slash mark. Repository is given in parentheses and USNM database numbers are listed.

Taxonomy
A key to adults of South American genera of Thaumaleidae is provided in Pivar et al. (2020).
Distribution. Chile and Australia. Species groups. Prior to this study, only five described species of Niphta were known from all regions and few phylogenetic affinities had been discussed. Theischinger (1986) suggested that the Australian N. farecta Theischinger was more closely allied to the Chilean N. nudipennis (Edwards) than the other Australian species. With the additional nine species described herein, it is now possible to better assess relationships based upon morphology. Species groups are proposed below for the genus Niphta.
The N. bickeli group: This group is characterised by the following features: broad gonocoxites extending to the posterior epandrial margin and lacking projections; long gonostyli; parameres fused medially, then separating into two arms that do not project anteriorly; a pair of apodemes from base of parameres extend to posterior margin of epandrium, on either side of the anus; cerci inconspicuous, thinly sclerotised and unpigmented; females lack projection at base of hypogynial valves. This group is greyish black in colouration. Additionally, immatures of N. collessi Theischinger lack ventral adhesive structures and protuberances on the larval head capsule (Sinclair 2000); these are tentatively seen as important characters uniting this species group until further Australian immatures are discovered and accurately associated with the adults (see discussion below comparing Niphta immatures). The N. bickeli group is found in Australia and includes the following species: N. bickeli Theischinger, N. collessi, and N. farecta. The N. halteralis group: This group is characterised by the following features: gonocoxites extending to midpoint of epandrium, lacking pointed projections; short and narrow gonostyli; parameres fused throughout; prominent cerci projecting anteriorly, extending well beyond posterior epandrial margin; females lack projection at base of hypogynial valves. This group is darkly coloured, mostly black and grey. Immature stages have ventral adhesive structures, are collected from rocky substrates and larval head capsules have many protuberances. The N. halteralis group is known from Chile and includes the following species: N. acus sp. nov., N. downesi sp. nov., N. halteralis (Edwards), and N. mapuche sp. nov.
The N. nudipennis group: This group is characterised by the following features: gonocoxites extending, at most, to midpoint of epandrium, and bearing pointed projections; broad, short gonostyli cheliform or finger-like; parameres fused medially. separated into two arms that project anteriorly and may be flexed or extended; cerci small, projecting anteroventrally; females possess distinct blunt or pointed projection at base of hypogynial valves; sternite 8 highly modified (genital fork and lateral arms); Female sternite 9 greatly expanded and heavily sclerotised, presumably reflecting the highly modified male genitalia. This group tends to be lighter in colouration. Immature stages have ventral adhesive structure, are collected from vegetation in splash zones, and larval head capsules have many protuberances. The N. nudipennis group is known from Chile and includes: N. bifurcata sp. nov.,N. bispinosa sp. nov.,N. brunnea sp. nov.,N. courtneyi sp. nov.,N. daniellae sp. nov.,N. eurydactyla sp. nov. and N. nudipennis. larger anterior projection (Figs 6D,8D Recognition. Niphta acus is recognised by the bifurcated apex of the gonostylus and the strongly apically tapered parameres, giving the appearance of a needle-like tip. Description. Male. n = 71. Length 1.6-2.5 mm. Colouration (Fig. 4A). Head dull, blackish brown; pronotum and postpronotum dark brown; postpronotal lobe brown with dark brown markings, light brown around anterior spiracle; prescutum, mesoscutum and pleura shiny, blackish brown; scutellum and mediotergite shiny, blackish brown; katepisternum dark brown with blackish brown markings, remaining pteropleuron mainly blackish brown with dispersed markings of brown to light brown; base of halter black, knob creamy yellow; legs greyish brown, apex of tarsi darker; abdomen blackish brown; terminalia concolourous with abdomen.
Head. Eyes above antennae broadly joined, with small triangular frons visible above antennae; frons with three to five strong setae. Flagellomeres 1-3 subquadrate, with flagellomere 1 expanded, 3 × as wide as next segment, equal to lengths of 2 and 3 combined; flagellomeres 4-10 cylindrical, becoming progressively thinner and elongate. Vertex with black setae of uniform length, with longer, black orbital setae.
Terminalia (Figs 2A,3A). Epandrium quadrate in ventral view, posterior margin rounded with large, medial indentation; long, extending well beyond gonostyli; without lobes or projections. Gonocoxites conical, one-third longer than wide, anterior margin rounded, expanded dorsally behind gonocoxal plate, nearly meeting medially, extended anteriorly toward sternite 8; posterior inner margin produced into rounded projection, outer margin without notch; inner margin densely setose. Gonostylus short, three-quarters length of cercus, strongly curved laterally throughout; widest at base, tapered toward bifurcated apex; outer margin bearing laterally directed setae. Parameres fused at gonocoxal apodeme, widest at point of fusion; extended beyond cerci; forming canal-like structure, flattened apically, tapered to off-centre sharp point (occasionally specimens with broken apex). Gonocoxal plate well sclerotised; tonguelike plate extended anteroventrally; hollow medially, pitcher plant-like; gonocoxal apodeme with secondary structure comprising three arms fused medially, running along interior of paramere canal, flaring into three or four filaments, projected ventrally at apex, with pair of lateral flanges near point of fusion. Cercus large, prominent; subquadrate; projected posteriorly; situated within epandrial indentation.
Abdomen. Subcylindrical, strongly tapered at caudal segment. Spiracles weakly developed, not projected or distinctly visible. Tergites 1-8 rectangular, without ridges; bearing pair of slender lateral setae above lateral margins and pair of slender dorsolateral setae. Tergite 9 rounded, posterior with dorsolateral ridges bearing pair of lateral setae and hind margin emarginated; projection directed posteriorly in lateral view. Sternites 3-8 rectangular, without row of faint setulae along anterior margin; lateral margins crenulate, bearing a few thin, short setae. Sternites 3 and 4 bearing pair of small lateral adhesive structures, sternite 5 bearing pair of large lateral adhesive structures on lateral margin. Caudal sternite subquadrate, with pair of posteriorly projected medial lobes; posterior margin with pair of medial ridges, curved dorsally forming small, dorsally projected tubercle in lateral view; without distinct caudal hooks.
Thorax. Prothorax with pair of anterodorsolateral protuberances bare; anterolateral protuberances with one long and two short setae; spiracular protuberance bearing two protuberances, inner protuberance with pair of setae, outer with single seta; pair of midlateral setae below anterolateral protuberance; three closely approximated setae near base of prothoracic leg (Keilin's organ). Mesothorax and metathorax with pair of dorsolateral protuberances bearing pair of closely approximated setae, one thickened, one slender; mesothorax with additional seta beneath protuberance; lateral protuberance on both segments bearing four setae; one long seta slightly ventral to lateral protuberance; three mid-ventrolateral setae directed ventrally. Prothorax bearing proleg, posterior half with rectangular adhesive structure; meso-and metathoracic sternites with rectangular adhesive structures.
Abdomen. Sternites 1-7 modified into circular, suction cup-like adhesive structures; sternite 8 with quadrate adhesive structure, extending over sternite 9; sternite 9 smooth, bearing anal proleg. Tergites 1-7 with single anterolateral protuberance on each side with single seta, and pair of posterodorsolateral protuberances, each bearing two closely approximated short, thin setae; lateral adhesive structure swelling bearing four setae, two lateral, two basal; additional single seta located anterior to lateral swelling. Segment 8 with dorsolateral protuberance on either side of posterior spiracular plate, each bearing pair of small setae; lateral protuberance with three setae; single short ventrolateral seta; ventral surface bearing pair of setae. Posterior spiracular plate with sclerite encircling procerci; procercus shorter than length of spiracular plate, bearing four setae, two thick, two slender; without cone-like protuberance on either side of procerci. Terminal segment with anterior dorsal protuberance bare; pair of posterior lateral protuberances with pair of setae; five lateral setae; two pairs of long setae on posterior margin, above pair of anal papillae; ventral sternite bearing single pair of setae.
Additional material examined. Known only from the type series.

Distribution.
Known from the south-central Andes of Chile (Fig. 24A); this species includes the northern-most record for Niphta in South America.
Etymology. The species name is from the Latin acu (needle, pin) in allusion to the needle-like tip of the paramere.
Bionomics. This species was collected at higher elevations than any other species in this publication. Larvae and pupae have ventral adhesive structures and were collected only from rocky substrates (Fig. 25). All immatures were collected from the margin of waterfalls, where water flow was quite slow. Recognition. This species is recognised by both filaments of the paramere and the aedeagal guide being easily visible in lateral view, giving it a tri-filamentous appearance. Also, the bend in the gonostylus is slightly stronger than that of N. mapuche.
Thorax. Antealar ridge bearing single pronounced, medial seta flanked by two smaller setae.
Wing. Wing length: 2.2-2.4 mm. C and posterior wing margin with fringe of microtrichia.
Female. Unknown. Immature stages. Unknown. Additional material examined. Known only from the type series. Distribution. Known from the foothills of the southern Andes in Chile (Fig. 24A). Etymology. Niphta downesi is named in honour of veterinary and medical entomologist J.A. Downes, who collected the first specimen of this species in 1985.

Type material examined. Holotype
Redescription. The redescriptions of N. halteralis differ from that of N. acus in the following regards: Male. n = 44. Length 1.3-2.0 mm. Colouration (Fig. 4C). Head dull, dark brown to black; postpronotal lobe, prescutum and mesoscutum shiny, brown, middle of postscutum light brown; scutellum and mediotergite shiny, light brown; pteropleuron light brown with dispersed dark brown markings; base of halter light brown, knob creamy yellow; legs pale brown, tarsi darker; abdomen dark brown, hind margins of tergites whitish; terminalia light brown.
Head. Frons with two strong setae. Flagellomeres 1-3 subquadrate, slightly expanded, 0.25 × as wide as next segment, slightly shorter than 2 and 3 combined. Vertex with yellow setae of uniform length, with longer, black orbital setae.
Thorax. Antealar ridge bearing single pronounced medial seta flanked by two smaller setae.
Terminalia (Figs 2C, 3C). Gonocoxite subquadrate; posterior inner margin produced into pointed projection; inner margin densely setose; outer margin without notch. Gonostylus short, about as long as cercus, widest at base, strongly tapered along outer margin with rounded apex; apex slightly flanged outward, appearing pointed in lateral view; distal half bearing setae along outer apical margin, a few setae on inner margin. Parameres fused at gonocoxal apodeme, widest medially, as wide as gonocoxite; extended past posterior margin of epandrium; lateral margins curved ventrally forming canal-like structure with median 'wings' projected posteriorly, margins feathered; apex with pointed hook-like projection, recurved and projected anteriorly to left. Gonocoxal plate well sclerotised; tongue-like plate extended anteroventrally; gonocoxal apodeme with secondary bridge connected with base of paramere. Cercus trapezoidal; projected posteroventrally.
Terminalia (Fig. 13C, D). Hypogynial valve with posterior margin deeply emarginated in ventral view, forming two triangular lobes. Tergite 9 oblong in lateral view, twice as wide as tergite 8. Sternite 9 (genital fork) slender, T-shaped; lateral arms not extended beyond hypogynial valve, Y-shaped; with ventral sclerite in hypogynial valve cleft. Two sclerotised, tube-like structures (perhaps spermathecal pumps) dorsal to base of lateral arms in lateral view; spermathecal receptacles and ducts not observed. Distribution. Known from both the Andes and Chilean Coastal Range in southern Chile (Fig. 24A).
Bionomics. This species appears restricted predominantly to low elevations in the Valdivian temperate rain forest. Recognition. This species is recognised by the paramere being mostly hidden within the epandrium in lateral view, giving the paramere a two-filament appearance. The gonostylus is less recurved than that of N. downesi.

Niphta mapuche
Description. The descriptions of N. mapuche differ from that of N. acus in the following regards: Male. n = 10. Length 1.4-2.5 mm. Colouration (Fig. 4D). Head dull, black; pronotum and postpronotum brown; prescutum and mesoscutum shiny, blackish brown, pleura brown; katepisternum brown with blackish brown margins; base of halter light brown turning black medially, knob creamy yellow; legs ranging from pale brown to blackish brown; abdomen blackish brown, posterior margins creamy; terminalia variable in colour from blackish brown to grey.
Abdomen. Abdominal sternite 2 with few setae restricted to laterad on posterior third; sternites 3-7 with setae restricted to lateral margins and middle third; sternite 8 with three or fewer setae medially and on lateral margins.
Terminalia (Figs 2D, 3D). Gonocoxite subquadrate; posterior inner margin slightly produced into pointed projection, outer margin notched. Gonostylus short, less than half-length of cercus, strongly curved lateroventrally throughout; apex pointed; outer margin bearing laterally directed setae. Parameres distally fused, widest at point of fusion; not reaching posterior margin of epandrium; dividing into two pointed, filamentous projections medially; shorter ventral filament not extended beyond gonostyli, apex directed posteriorly; longer dorsal filament not extended to posterior margin of epandrium, at most slightly beyond base of cercus, apex projected slightly posterodorsally. Gonocoxal plate broad, well sclerotised, tongue-like plate extending anteroventrally; gonocoxal apodeme with secondary structure comprising single short, indistinct filament, running along interior of paramere, ending before apical margin of gonostylus. Cercus trapezoidal.
Thorax. Hindleg concealed behind wing sheath, only apex visible between apex of foreleg and wing sheath, slightly shorter than foreleg, but longer than wing sheath. Wing sheaths with large tubercle at base, setae not visible.
Abdomen. Setae not visible on tergites 1-8. Larva. n = 17. Length of final instar 6.3-6.7 mm. Colouration. Head capsule variable, ranging from light brown to black. Body mottled brown and grey, possibly pale brown to creamy; cream coloured ventrally.

Additional material examined.
Known only from the type series. Distribution. Known from the southern Andes of Chile (Fig. 24A). Etymology. This species is named after the Mapuche (mapu, land, che, people) indigenous peoples, who since ~ 500 B.C., have inhabited the regions of southern Chile, where N. mapuche is known.
Bionomics. This is a mid-elevation species. Adults were observed flying around and resting on leaf tips, roughly two meters from the nearest splash zones. Larvae and pupae have ventral adhesive structures and were collected only from rocky substrates at the margin of a waterfall. Recognition. This species is recognised by the bifurcate, posterior apex of the cheliform gonostylus and the bifurcate anterior projection of the gonocoxite. It is darker in colouration compared to the closely related N. courtneyi.
Head. Eyes above antennae broadly joined, with small triangular frons visible above antennae; frons with two strong setae. Flagellomeres 1-3 subquadrate, 1 expanded, twice as wide as next segment, shorter in length than 2 and 3 combined; flagellomeres 4-10 cylindrical, becoming progressively thinner and elongate. Vertex with black setae of uniform length, with longer, black orbital setae.
Terminalia (Figs 6A, 8A). Epandrium quadrate in ventral view, posterior margin rounded, with medial cleft; long, extended beyond gonostyli; without lobes or projections. Gonocoxites oblong, longer than wide; anterior margin rounded, somewhat expanded dorsally behind gonocoxal plate, not closely approximated; with two spinelike projections; anterior projection wide, bifurcate; posterior projection long, slender, slightly sinuous, tapered to single apex, nearly twice as long as anterior projection; inner margin with numerous long, thin setae. Gonostylus cheliform, dorsoventrally flattened anteriorly, swollen posteriorly; anterior apex with a few setae; posterior apex bifurcate, setose. Parameres medially fused, attached basally to arms of gonocoxal plate; divided distally into dorsal parameral apodeme and ventral arm; ventral arm projected anteroventrally toward gonocoxal plate, strongly curved anteriorly, sickle-shaped, surface textured with tiny bumps, except for smooth apex; ventral arm extends posteroventrally presumably to aid in copulation; when retracted, rests ventrally between dorsal arm of gonocoxal plate and dorsal to anterior gonocoxal projection. Gonocoxal plate broad, well sclerotised; anterior margin subquadrate, basal margin cleft; pair of dorsal arms connected to parameres; medial aedeagal guide projected ventrally between posterior margins of gonocoxites, well sclerotised, comprising two parts: anterior Y-shaped structure with five finger-like projections protruded from posterior margin and dorsal trian- Female. n = 1. Similar to male except as follows: Abdomen. Tergite 9 noticeably more sclerotised than preceding tergites; sternite 8 well sclerotised, with distinct blunt projection at base of hypogynial valve. Terminalia (Figs 11A, 12A). Hypogynial valve not projected beyond tergite 9; posterior margin deeply cleft in ventral view, forming two triangular lobes; lobes densely setose, with both stout, thickened setae and thinner, long setae with slight apical bend; hypogynial protuberance between valves. Tergite 9 subquadrate in lateral view, 1.5 × as wide as tergite 8, lacking lateral projections. Sternite 9 (genital fork) slender, Y-shaped at both ends; lateral arms forming complex of highly modified structures: medial heavily sclerotised circular opening, dorsal to posterior cleft of hypogynial valve, with pair of lateral sclerotised triangular expansions; triangular expansions expanded dorsally into pair of circular plates, those further expanded anteriorly into pair of heavily sclerotised plates, strongly recurved posteroventrally toward circular opening, remaining dorsal to genital fork; dorsal surface of recurved plates with tiny grooves and indentations. Hypoproct lightly sclerotised, narrow. Cercus quadrate, projected posteroventrally; bearing numerous setae. Spermathecae not observed; two spermathecal ducts visible in centre of lateral arm circle.
Immature stages. Unknown. Additional material examined. Known only from the type series. Distribution. Known only from the type locality in the Chilean Coastal Range (Fig. 24B).
Etymology. Niphta bifurcata is named in reference to the posterior apex of the gonostylus and the anterior projection of the gonocoxite, both of which are bifurcate. Recognition. This species is recognised by the cheliform gonostylus with nonbifurcate apices and the gonocoxite with two projections, the anterior one long and bifurcate, the posterior one small, tooth-like. It is lighter in colouration than the closely related N. brunnea. Description. The descriptions of N. bispinosa differ from that of N. bifurcata in the following regards:
Head. Frons with three strong setae. Flagellomere 1 expanded, 1.5 × as wide as next segment, equal in length to 2 and 3 combined.
Female. n = 2. Similar to male except as follows: Terminalia (Figs 11C, 12C). Posterior margin of hypogynial valve deeply cleft in ventral view, forming two quadrate lobes. Tergite 9 twice as wide as tergite 8. Sternite 9 (genital fork) slender, Y-shaped at both ends; lateral arms forming complex of highly modified structures: medial heavily sclerotised circular opening, dorsal to posterior opening of hypogynial valve, with pair of lateral sclerotised triangular expansions. Spermathecae not observed.
Immature stages. Unknown. Additional material examined. Known only from the type series. Distribution. Known only from the type locality in central Chile (Fig. 24B).

Niphta brunnea
Recognition. This species is recognised by the cheliform gonostylus bearing nonbifurcate apices and the gonocoxite with three projections: two that are nearly equal in size and the third, much smaller and inconspicuous, situated at the base of the anterior one. It is darker in colouration compared to the closely related N. bispinosa, and the darkest of the N. nudipennis group.
Description. The descriptions of N. brunnea differ from that of N. bifurcata in the following regards: Male. n = 5. Length 1.6-1.9 mm. Colouration (Figs 9B, 10B). Pronotum and postpronotum brown; remaining scutum shiny, brown, pleura light brown; scutellum shiny, brown; mediotergite shiny, anterior half light brown, posterior half dark brown; katepisternum mainly brown, lighter near anterior spiracle; remaining pteropleuron mainly brown with dispersed markings of dark/light brown; base of halter creamy, distal half of stalk and knob light brown; abdomen brown; terminalia light brown.
Head. Flagellomere 1 expanded, 1.5 × as wide as next segment, shorter in length than 2 and 3 combined.
Wing. Wing length: 1.9-2.2 mm. Terminalia (Figs 6D, 8D). Epandrium quadrate in ventral view, posterior margin rounded, with narrow medial cleft; long, extended beyond gonostyli; without lobes or projections. Gonocoxites oblong, longer than wide; anterior margin rounded, somewhat expanded dorsally, not closely approximated; with three spine-like projections; large anterior projection nearly equal in length to posterior projection, gradually tapered toward apex; smaller anterior projection positioned somewhat anterior to large tooth, may be small and inconspicuous in some specimens; posterior projection strongly tapered toward apex, some specimens with second basal tooth on outer margin of projection; margin around anterior projection with long, thin setae. Gonostylus cheliform, dorsoventrally flattened, margins concave creating bowl-like appearance; anterior apex with a few indistinct setae, posterior margin with strong setae. Parameres medially fused, attached basally to arms of gonocoxal plate; divided distally into dorsal parameral apodeme and ventral arm; ventral arm projected anteroventrally toward gonocoxal plate, knife-shaped, ventral margin serrate; when retracted, resting ventrally between dorsal arm of gonocoxal plate and inner margin of gonocoxite, apex reaching base of anterior gonocoxal projection. Gonocoxal plate broad, well sclerotised; anterior margin triangular, basal margin cleft; pair of dorsal arms connect to parameres; medial aedeagal guide projected ventrally between gonostyli, well sclerotised, consisting of two parts, anterior structure with five projections and posterior rounded plate bearing minute setulae. Cercus ovoid, only slightly visible in lateral view; projected anteroventrally; situated within epandrial indentation.
Thorax. 1.5 × wider than abdomen at widest point. Foreleg sheath projected straight and slightly beyond wing sheaths, reaching hind margin of sternite 2; anterior half of midleg visible anterior to wing sheath, then hidden behind foreleg, not projected beyond wing sheath; hindleg concealed beneath wing sheath, only small Respiratory organ slightly shorter than maxillary sheath, broadest subapically; ovate, slightly arched medially, tapered toward apex; spiracular openings encircling apex; stalk thin, emerging from small tubercle. Tubercle situated posterodorsally to respiratory organ, rounded, projected laterally; apex nearly touching or touching respiratory organ. Thorax devoid of setae.
Thorax. Prothorax with single pair of protuberances bearing single spiracle; spiracular protuberance bearing one pair of dorsal setae anterior to spiracle and single dorsolateral seta; three mid-lateral setae, two long, one short and fine; two closely approximated setae near base of prothoracic leg (Keilin's organ). Mesothorax and metathorax with pair of small dorsolateral protuberances and pair of large lateral protuberances; mesothoracic dorsolateral protuberance bearing single thickened seta, metathoracic lateral protuberance bearing pair of closely approximated setae, anterior seta thickened and longer than posterior seta; lateral protuberance on both segments bearing three setae, two short, one long; single long seta slightly ventral to lateral protuberance; one pair of mid-ventrolateral setae. Prothorax bearing proleg, posterior half with rectangular adhesive structure; meso-and metathoracic sternites with rectangular adhesive structure.
Abdomen. Sternites 1-7 modified into circular, suction cup-like adhesive structure; sternite 8 with quadrate adhesive structure; sternite 9 smooth, bearing anal proleg. Segments 1-7 lacking distinct protuberances, at most, pair of dorsolateral swellings bearing single or paired short, thin setae; single seta situated anterolaterally; lateral adhesive structure swelling bearing numerous setae, two anterolateral, two midlateral, four basalateral. Segment 8 with small dorsolateral protuberance on either side of posterior spiracular plate, each bearing pair of small setae; lateral protuberance with single seta; single short ventrolateral seta; ventral sternite bearing pair of setae. Posterior spiracular plate with sclerite encircling procerci; procercus shorter than length of spiracular plate, bearing four setae, two thick, two slender; without cone-like protuberance on either side of procerci. Terminal segment with pair of protuberances, no setae; pair of dorsolateral setae; five lateral setae; two pairs of long setae on posterior margin, above pair of anal papillae; ventral sternite lacking setae.
Additional material examined. Known only from the type series. Distribution. Known only from two localities in the Andes of southern Chile (Fig. 24B).
Etymology. Niphta brunnea is from the Latin brunneus (brown) in allusion to its brown colouration, the darkest of the N. nudipennis group.
Bionomics. The larvae and pupae both possess the ventral adhesive structures seen in other known immature stages of South American Niphta. Immatures were  collected from wetted vegetation in the splash zones, never from rocks ( Fig. 26A-C). Vegetation included both living and dead plant material, including smooth leaves and herbaceous stems. The vegetation was not in the direct flow of water, but rather lightly splashed by water droplets that maintained enough moisture for the immatures to survive. Recognition. This species is recognised by the bifurcate posterior apex of the cheliform gonostylus and the presence of three gonocoxal projections. It is lighter in colouration than the closely related N. bifurcata.
Description. The descriptions of N. courtneyi differ from that of N. bifurcata in the following regards: Male. n = 1. Length 2.1-2.3 mm. Colouration (Figs 9C, 10C). Head dull, brown; pronotum and postpronotum brown; postpronotal lobe and lateral margins of prescutum yellow; scutum shiny with three distinct dark brown stripes, pleura yellow; postscutum yellow, two lateral brown spots above scutoscutellar suture; scutellum shiny, yellow; mediotergite shiny, anterior half yellow, posterior half brown; katepisternum mainly pale brown, yellow near fore coxa; remaining pteropleuron mainly yellow with dispersed brown markings; halter creamy yellow; legs pale yellow, apex of tarsi darker; abdomen brown; terminalia yellow.
Head. Frons with three strong setae. Flagellomere 1 expanded, 1.5 × as wide as next segment, shorter in length than 2 and 3 combined.
Immature stages. Unknown. Additional material examined. Known only from the type series. Distribution. Known only from the type locality, the East side of Lago Llanquihue in Southern Chile (Fig. 24B).
Etymology. Niphta courtneyi is named in honour of its collector, Gregory W. Courtney (Iowa State University). Courtney collected three new species of Thaumaleidae from Chile (A. fredericki Pivar, N. courtneyi, and N. mapuche), as well as immature material, prompting us to further investigate the Chilean fauna.  Recognition. This species is recognised by the sharply pointed, tapered gonostylus with no projections and not cheliform, unlike all remaining species in the N. nudipennis group. The gonocoxal plate also has a pair of lateral arms projected anteriorly.

Niphta daniellae
Description. The description of N. daniellae differs from that of N. bifurcata in the following regards: Male. n = 2. Length 1.7-2.0 mm. Colouration (Figs 9D, 10D). Postpronotal lobe and lateral margins of prescutum yellow; scutum shiny with three distinct brown stripes, pleura yellow; postscutum yellow, two lateral brown spots above scutoscutellar suture; scutellum shiny, yellowish; mediotergite shiny, anterior half yellow, posterior half brown; katepisternum dark brown, except yellow at base of fore coxa; anepisternum and paratergite brown; remaining pteropleuron yellow; halter entirely creamy yellow; legs yellowish brown, tarsi dark brown; abdominal tergites brown, posterior margin pale brown, sternites mainly yellow with scattered brown markings; terminalia yellowish brown. Head. Frons with two to three strong setae. Flagellomere 1 expanded, 1.5 × as wide as next segment, subequal in length to 2 and 3 combined.
Female. Unknown. Immature stages. Unknown. Additional material examined. Known only from the type series. Distribution. Known from two localities in the Andes of south-central Chile (Fig. 24B).
Etymology. This species is named in honour of RJP's wife, Danielle Lombardi, for her support during Pivar's graduate research and entomological endeavours, and for playing an important role in organising the Chilean expedition. Raised in northern Chile (Arica), Danielle's Spanish skills were critical for translating all communications with government and national park contacts, as well as translating our requests for collecting permits. Recognition. This species is recognised by a broad, straight, finger-like projection on the gonostylus.
Description. The description of N. eurydactyla differs from that of N. bifurcata in the following regards: Male. n = 17. Length 1.5-1.8 mm.
Colouration (Figs 9E, 10E). Variable colouration, even among specimens from the same population; base colouration of thorax either yellow or orange as follows: post- pronotal lobe and lateral margins of prescutum orangey/yellowish brown; scutum shiny with three distinct brown stripes, pleura yellow to yellowish brown; postscutum orangey/ yellowish brown, two lateral brown spots above scutoscutellar suture; scutellum shiny, orangey/yellowish brown; mediotergite shiny, anterior half orangey/yellowish brown, posterior half brown; katepisternum mainly pale brown with scattered orange/yellow and black markings, or mostly yellowish brown with brown lateral markings above mid coxae; paratergite brown; remaining pteropleuron mainly orangey-brown to yellowish brown with dispersed markings of brown and black; base of halter creamy grey, knob pale yellow; legs pale brown, apex of tarsi darker; abdomen brown; terminalia pale brown.
Thorax. Antealar ridge bearing three to four setae, middle seta most pronounced.
Female. Unknown. Immature stages. Unknown. Additional material examined. Known only from the type series. Distribution. Known from both the Chilean Coastal Range and Andes of southern Chile (Fig. 24B).
Pupa. n = 4 (Figs 14B, 15B, 16B). Length 3.0-3.1 mm. Colouration. Light brown; with black spot above eyes in developing adult. Thorax. 1.25 × wider than abdomen at widest point. Foreleg sheath projected straight, slightly shorter than wing sheaths; anterior half of midleg visible anterior to wing sheath, then hidden behind foreleg, apices visible, slightly longer than foreleg; hindleg concealed beneath wing sheath, only apex visible between apex of foreleg and wing sheath, longer than foreleg, extended slightly beyond wing sheath but not reaching hind margin of sternite 2. Wing sheaths not reaching posterior margin of abdominal sternite 2. Respiratory organ slightly longer than maxillary sheath, broadest subapically. Tubercle situated posterodorsally to respiratory organ, rounded, projected slightly posterolaterally; apex well separated from respiratory organ. Thorax devoid of setae.
Colouration. Head capsule pale brown (sometimes dark brown). Body creamy brown.
Head capsule (Fig. 21C, D). Five pairs of tubercles outside of ecdysial lines (not including antennal and ocular tubercle), all smaller than ocular tubercle; 2 tubercles between ecdysial lines, upper tubercle larger than lower.
Thorax. Spiracular protuberance bearing one pair of dorsal setae anterior to spiracle and single lateral seta.
Abdomen. Segments 1-7 with lateral adhesive structure inflatted bearing four setae, two midlateral, two basalateral. Terminal segment with pair of protuberances bearing pair of setae; four lateral setae, two long, two short and fine. Distribution. Known from both the Chilean Coastal Range and the Andes of southern Chile (Fig. 24B).
Bionomics. Niphta nudipennis is a low-elevation species inhabiting the Valdivian temperate rainforest. Adults were collected mainly from foliage around splash zones (Figs 26D, 27A, F). The larvae possess the ventral adhesive structures found in the N. halteralis group; however, they were only collected from overhanging vegetation in the splash zone. Vegetation included both living and dead plant tissue, on textures spanning smooth leaf surfaces, to more textured fern fronds and herbaceous stems (Fig. 26E). Pupae were collected from the same habitats and also possess adhesive structures. The amount of water splashing on the vegetation appeared to be just enough to keep it damp enough to keep the immatures alive.

Discussion and conclusions
Immature stages of South American Niphta Pivar et al. (2018b) described the first immatures for South American thaumaleids, where the larva and pupa of Neothaumalea atlantica were described. Sinclair (2000) described the larva and pupa of N. collessi, an Australian species and the first for the genus. The remarkable immatures described herein are the first for South American Niphta and reveal unique evolutionary adaptations for the family. Unlike other described thaumaleid species, including N. collessi, immature South American Niphta are equipped with ventral adhesive structures, resembling suction cups. They are present on nearly all segments of the larva and on segments 3-5 of the pupa, and presumably aid in maintaining their position within the flow of water. The known immatures of the N. halteralis species group (N. acus and N. mapuche) were both collected from rocky substrates (Fig. 25), whereas the known immatures of the N. nudipennis species group (N. brunnea and N. nudipennis) were collected from vegetation in the splash zones, the first such observation for the family (Fig. 26).
Each group's morphology is well adapted to their microhabitat. On a rock face, immatures have to contend with debris being washed down from the substrate above. Pupae of the N. halteralis group were collected from exposed microhabitats on the rock face, with no protection from flowing debris. Their stout and stocky body shape, hidden spiracles and small respiratory organs that do not extend far from the body, likely help in withstanding any potential debris impact and reduce breakage of exposed appendages. Both pupae and larvae are mottled and much darker in colouration than the pupae of the N. nudipennis group, offering greater camouflage from predators on the exposed rock face. Larvae have the added vestiture of dorsal tubercles, which help to break up the outline of the body. Immatures of the N. halteralis group also bear more setae than species of the N. nudipennis group, perhaps for sensing debris or predators that may be nearby.
Immatures of the N. nudipennis group were all collected from plant material, either living or dead, but always directly in the splash zone. They were collected from both smooth leaf surfaces and more textured vegetation, such as ferns and herbaceous plant stems. They were found on both upper and lower leaf surfaces, depending on which surface was in the splash zone. Contrary to a rock face, the amount of debris flowing down a leaf is likely minimal. Pupae of the N. nudipennis group are conoid, with a broad head and thorax and a narrow abdomen, protruding spiracles, and large, laterally projecting respiratory organs. All of these features are indicative of life in a habitat where debris does not pose a problem of displacement, breakage, or blockage of the respiratory organ. The leaf habitats were generally shaded and hidden from direct view, and coupled with constant splashing, individuals may experience less predation than on a rock face, thereby reducing the need for the dark, mottled colouration and tubercles. Eggs on vegetation were not observed, nor was oviposition by the adults, but they are presumably laid on the vegetation surface.
The presence of the adhesive structures is associated with behavioural traits that differ from those of other Thaumaleidae. The typical thaumaleid larva will exhibit a characteristic quick, sidewinding motion to evade predation (Thienemann 1909;Sinclair 2000;Pivar et al. 2018a). Chilean Niphta are much slower when trying to escape, almost caterpillar-like in movement, with slow, undulating motions. The thoracic adhesive structures are rectangular in shape and are more mobile than those of the abdominal segments, which are circular (Fig. 23).
Despite the discovery of this new larval morphotype, specimens were never collected in areas of extremely high flow or aggressive splash zones; rather, they were collected in typical thaumaleid habitat consisting of slow flowing, thin films of water. Perhaps antecedents originated in environments with higher water flow, such as in a river, and the extant species are a result of having adapted to the more familiar recent habitats. Alternatively, these slow flowing zones may be subject to torrential flooding after rainfall. The continued presence of the adhesive structures suggests a continuing evolutionary advantage in their present-day habitat.

Comparison of Niphta immatures
Immatures of the Australian N. collessi (Sinclair 2000) differ from Chilean Niphta most notably in the absence of the ventral adhesive structures. Several other characters also warrant discussion.
The pupa of N. collessi has caudal hooks, much like in Neothaumalea atlantica; however, the Chilean species lack caudal hooks or any other projections. There is also a significant reduction in setae, both in number and length. Niphta collessi has numerous setae, many of which are long, while members of the N. halteralis group have very few, short setae. Pupae of the N. nudipennis group lack abdominal setae altogether. The respiratory organs of N. collessi are similar in appearance to those of the N. nudipennis group, where they are broadest subapically and project laterally, whereas those in the N. halteralis group are shorter and barely project laterally. The spiracles of N. collessi and the N. nudipennis group are also similar; well developed on sternites 3-7 and mounted on long, narrow, lateral tubercles. The spiracles are barely visible in the N. halteralis group.
The larvae also exhibit some significant differences and similarities. The most apparent difference, aside from the adhesive structures, is in the sculpture of the head capsule. All described Chilean Niphta have protuberances and large antennal tubercles, similar to those of Neothaumalea atlantica; Niphta collessi lacks protuberances and the antennae are on short tubercles. Also, much as in the pupae, Chilean Niphta larvae exhibit a reduction in setae compared to N. collessi. Another significant difference is the presence of cauliflower-like protuberances on both thoracic and abdominal tergites. These protuberances are especially prominent in the N. halteralis group, and are reduced but still present in Ni. nudipennis group. Based on Sinclair's (2000) description, it appears that N. collessi lacks all protuberances and is more reminiscent of Austrothaumalea larvae. Similarities between the two faunas are: larval head-capsule with sensory pit 13 near dorsal margin of antenna, head-capsule only with simple setae and the caudal lobes flanking posterior spiracular plate are absent. Since descriptions of the immature stages of N. collessi are based on a single pupa and attached larval exuviae, additional collections of the immature stages are needed urgently to verify our comparisons.
Larvae with ventral adhesive structures have been collected in Australia. Though they have not been reared, nor identification confirmed via DNA fingerprinting (attempts to fingerprint were made, but with no success), morphology indicates these larvae are likely a member of Niphta. They appear very similar to members of the N. halteralis group: presence of distinct thoracic and abdominal protuberances, darker colouration, long abdominal setae (longer and more abundant than N. halteralis group) and pronounced head-capsule protuberances (not as large as N. halteralis group, but larger than N. nudipennis group). The adhesive structures appear very similar between all species: thoracic segments rectangular, adhesive structures felt-like; abdominal segments 1-7 circular, margins felt-like with smooth interior; abdominal segment 8 quadrate, felt-like (Fig. 23). Continued sampling on both continents will provide further insight into the evolution of Niphta.

Faunal patterns and habitat
South American thaumaleid diversity has now increased to 17 described species. Additionally, there is the likely new species to be discovered in Ecuador, plus three more new species from Chile that were collected by the authors, but not yet described because they are represented by females only. Since males possess readily recognised genitalic features, the authors have decided to wait until further material is collected before describing these species. Both morphological and molecular data (Pivar, unpublished data) support the presence of these new species. Of the described South American species, only Neothaumalea atlantica is not found in the Andes Range and is recorded from the Atlantic Forest of southeastern Brazil, in the Serra Geral mountains (Pivar et al. 2018b). The remaining species range along a roughly 2000 km stretch of the south-central Chilean Andes, with only three records from the Argentinian side, all from Bariloche. The Andes are the longest mountain range in the world at roughly 7000 km long, running from the southern tip of Chile, north to Venezuela. There are only 16 described species from ~20% of sampled mountain range. The South American fauna is undoubtedly more diverse than is presently known and current numbers are reflective of under sampling.
In Chile, thaumaleid diversity increases as one moves south. Beginning in central Chile and progressing south, the following are the known diversity of species per region (including the three undescribed females): Valparaíso (1 sp.), Santiago (2 spp.), O'Higgins (1 sp.), Maule (2 spp.), Bío Bío (5 spp.), Araucanía (7 spp.), Los Ríos (6 spp.), Los Lagos (8 spp.) and Aysén (1 sp.). These numbers are reflective of both the amount of time spent collecting in certain regions and regions sampled; some regions have likely never been sampled (particularly in northern Chile). Available habitat is also a large contributor to diversity. From Bío Bío to Los Lagos, specimens were collected in Valdivian temperate rainforests, characterised by high rainfall and cooler temperatures. Vegetation types include southern beech, laurel and broadleaved forest, bamboo and ferns. With an abundance of mountain streams and waterfalls, similar to the Nearctic Pacific Northwest (Pivar et al. 2018a), there is ample habitat for thaumaleids. From Valparaíso to Maule, habitat availability begins to drop drastically, in particular from Valparaíso to O'Higgins. These regions are part of the Chilean Matorral ecoregion of central Chile, characterised by a temperate Mediterranean climate and sclerophyllous shrubs and trees, and cacti (Meserve et al. 2019). Summers are dry and hot, and madicolous habitats scarce, as suggested by the diversity listed above. The western slopes of the Andes, from Santiago in central Chile to northern Peru, become extremely dry as they transition into the Atacama Desert. Suitable habitat is scant in these areas, though the eastern slopes of Argentina, Bolivia and Peru may contain more suitable habitat as they receive more moisture.
Most Chilean species are found in temperate rainforest regions, but some are found in both wet and dry climates (A. chilensis Edwards, N. acus). The type of madicolous habitat (i.e., creek, rock face seep, stream, waterfall, etc.) (Fig. 27) does not seem to dictate where a particular species may be found; oftentimes, species were collected in multiple habitat types. Multiple species and genera were frequently collected together, both within the same species group and mixed groups.
Future collections should focus on all areas of the Andes, with an emphasis on the northern sections to provide insight into the northern limits of the family and genera. Currently, the southern-most Nearctic species is Androprosopa zempoala Sinclair and Huerta from central Mexico (Sinclair and Huerta 2010) and the northern-most South American species is the undescribed specimen from Ecuador. Thaumaleids are not recorded from Central America (Brown et al. 2009), so what is the northern limit of the South American genera? Does one genus become more abundant than the other at higher/lower latitudes or elevations? Other mountain ranges on the continent should be explored, such as the Sierras de Córdoba (central Argentina), the Sierra Nevada de Santa Marta (northern Colombia), and continued studies in Brazil will surely lead to new discoveries. Focused collecting efforts in these regions will answer these questions, as well as divulge the true breadth of South American thaumaleid diversity.