Niarchos, Platnick, Norman I. & Dupérré, Nadine, 2010

Platnick, Norman I. & Dupérré, Nadine, 2010, The Andean Goblin Spiders Of The New Genera Niarchos And Scaphios (Araneae, Oonopidae), Bulletin of the American Museum of Natural History 2010 (345), pp. 1-120 : 6-9

Niarchos , new genus

TYPE SPECIES: Niarchos cotopaxi , new species.

ETYMOLOGY: The generic name honors Constantine Niarchos , in recognition of the vital support obtained from the Constantine Niarchos Expedition Fund ; the gender is masculine.

DIAGNOSIS: Members of this genus resemble those of Scaphiella and Escaphiella in having a dorsal abdominal scutum in males that is absent in females, but they differ obviously in having much thicker emboli on the male palps and a much smaller postepigastric abdominal scutum in females. The closest relatives of the species treated here (aside from those treated below as Scaphios ) seem to be undescribed (which is hardly surprising in a family where 75 % or more of the extant species have yet to be described), and occur in northern South America. Those undescribed taxa resemble Niarchos species also in their unusual leg spination patterns, with macrosetae absent on legs I and II, but occurring ventrally on tibiae and/or metatarsi III and/or IV (figs. 57, 58). The combined presence of a wide cymbium that lacks a distinct delimitation from the palpal bulb (figs. 75, 270, 516, 608), the reduced size of the posterior eyes (figs. 43, 242, 492, 575), and the triangular, posteriorly directed anterior projections on the male endites (figs. 49, 247, 497, 581) separates Niarchos species from each of their undescribed relatives that we have studied to date.

DESCRIPTION: Total length of males 1.1– 2.1, of females 1.3–2.4; carapace orange, sternum, chelicerae, endites, labium, legs, and palpi pale orange; dorsal and ventral scuta of males pale orange, epigastric and postepigastric scuta of females yellow, soft portions of abdomen white, often iridescent. Cephalothorax: Carapace without any pattern, elongate oval in dorsal view, pars cephalica slightly elevated in lateral view, anteriorly narrowed to between 0.5 and 0.75 times its maximum width, with rounded posterolateral corners; posterolateral edge without pits, posterior margin not bulging below posterior rim, anterolateral corners with slightly sclerotized triangular projections, posterolateral surface without spikes, surface of elevated portion of pars cephalica smooth, sides finely reticulate; pars thoracica without depressions, fovea absent, without radiating rows of pits; lateral margin straight, smooth, without denticles; plumose setae near posterior margin of pars thoracica absent; nonmarginal pars cephalica setae dark, needlelike, scattered; nonmarginal pars thoracica setae absent; marginal setae dark, needlelike. Clypeus margin slightly rebordered, curved downward in front view, vertical in lateral view, low, ALE separated from edge of carapace by less than their radius, median projection absent; setae dark, needlelike. Chilum usually absent, but present as wide triangle in N. cotopaxi , as tiny sclerite in N. barragani . Eyes six, posterior eyes reduced in size, much smaller than ALE; all eyes oval; posterior eye row procurved from front, slightly procurved, straight, or slightly recurved from above; ALE separated by less than their radius, ALE-PLE separated by less than ALE radius, PME usually separated by less than their radius (exceptions noted in species descriptions). Sternum longer than wide, coloration uniform, not fused to carapace, median concavity absent, without hair tufts, with radial furrows between coxae I–II, II–III, III–IV, furrows smooth, radial furrow opposite coxae III absent; surface finely reticulate or smooth, without pits (other than setal bases), microsculpture covering entire surface, sickleshaped structures absent; anterior margin unmodified, posterior margin extending posteriorly of coxae IV only as prongs reaching to sides of pedicel, anterior corner unmodified, lateral margin without infracoxal grooves, distance between coxae approximately equal, precoxal triangles present, lateral margins unmodified, without posteri- or hump; setae sparse, dark, needlelike, densest laterally, originating from surface; sternum of females followed posteriorly by small ventral pedicel sclerite. Chelicerae straight; without teeth on promargin or retromargin, anterior face with basal swelling; fang without toothlike projections, directed medially, shape normal, without prominent basal process, tip unmodified; setae dark, needlelike, densest medially; paturon inner margin with scattered setae, distal region abruptly narrowed, posterior surface unmodified, promargin unmodified, inner margin unmodified, laminate groove absent. Labium triangular, not fused to sternum, anterior margin indented at middle, same as sternum in sclerotization, with six or more setae on anterior margin, subdistal portion with unmodified setae. Endites distally not excavated, serrula present in single row, anteromedian tip with posteriorly directed triangular projection in males, unmodified in females, posteromedian part unmodified, same as sternum in sclerotization. Female palp without claw; with long bristles but without spines; tarsus unmodified, patella without prolateral row of ridges. Abdomen: Without color pattern, cylindrical, without long posterior extension, rounded posterior- ly, interscutal membrane with setae, without rows of small sclerotized platelets. Book lung covers large, ovoid, without setae, anterolateral edge unmodified. Posterior spiracles connected by groove. Pedicel tube short, briefly ribbed in males but unmodified in females, scuto-pedicel region unmodified, scutum extending far dorsal of pedicel in males (but not females), plumose hairs absent, matted setae on anterior ventral abdomen in pedicel area absent, cuticular outgrowths near pedicel absent. Dorsal scutum present in males (but not females), strongly sclerotized, without color pattern, covering most of dorsum but not fused to epigastric scutum (except in N. michaliki and N. ligiae , where reduced to narrow longitudinal strip confined to cardiac area and fused to epigastric scutum), anteriorly narrowed, surface finely reticulate, anterior half without projecting denticles. Epigastric scutum of males strongly sclerotized, surrounding pedicel, not protruding, small lateral sclerites absent, fused to long, strongly sclerotized postepigastric scutum occupying most of venter (except in N. michaliki and N. ligiae , where confined to epigastric area); epigastric scutum of females weakly sclerotized, not surrounding pedicel, without lateral joints, not fused to postepigastric scutum, that scutum weakly sclerotized, yellow, confined to area between epigastric furrow and groove connecting posterior spiracles; postepigastric scutum anterior margin unmodified in both sexes, without posteriorly directed lateral apodemes in males, usually with apodemes in females. Supraanal scutum absent. Dorsum setae dark, needlelike, epigastric area setae uniform, dark, needlelike, postepigastric area setae dark, needlelike, dense patch of setae anterior to spinnerets absent. Spinneret scutum usually reduced to pair of small lateral plates, situated near bases of anterior lateral spinnerets, bearing setae, but apparently absent in N. michaliki , plates fused into single median triangle in N. palenque and N. facundoi , fused into single median strip in N. loja , consisting of four lateral plates (two anterior of others) in male N. foreroi , of two lateral plates and fused anterior strip in female N. foreroi . Dorsum setae dark, needlelike; epigastric area setae uniform, dark, needlelike; postepigastric setae dark, needlelike; dense patch of setae anterior to spinnerets absent. Interscutal membrane with setae. Colulus absent. Spinnerets scanned only in N. barragani , N. scutatus , and N. palenque ; anterior laterals with single major ampullate gland spigot and three piriform gland spigots; posterior medians with one, two, or three spigots; posterior laterals with two or three spigots in males, three or five in females (figs. 69–72, 107, 263–266, 295–298, 589–592, 625–628). Legs: Without color pattern; femur IV not thickened, same size as femora I–III, patella plus tibia I shorter than carapace, tibia I unmodified, tibia IV specialized hairs on ventral apex absent, tibia IV ventral scopula absent, metatarsi I, II mesoapical comb absent, metatarsi III, IV weak ventral scopula absent. Leg spines present as slightly enlarged, greatly darkened macrosetae on ventral surface of tibiae (and sometimes metatarsi) IV (and sometimes III). Superior claws with few large teeth situated distally on lateral surface, many small teeth situated proximally on median surface, inner face striate; inferior claws absent. Trichobothrial base with opening longitudinally narrowed, aperture internal texture gratelike, hood covered by numerous low, closely spaced ridges (figs. 105, 292, 520, 588). Tarsal organ of legs I, II with three sensillae, of legs III, IV, and palp with two sensillae (figs. 59–63, 95–99, 250–254, 287–291, 509– 513, 542–546, 602–606, 633–637). Genitalia: Male epigastric region with sperm pore situated at level of anterior spiracles, usually small, circular, unmodified; epigastric furrow without V -shaped insertions, without setae. Male palp of normal size, not strongly sclerotized, right and left palps symmetrical; trochanter of normal size, unmodified; femur of normal size, two or more times as long as trochanter, without posteriorly rounded lateral dilation, attached to patella basally; patella about as long as femur, slightly wider than femur, without prolateral row of ridges, setae unmodified; tibia with two or three trichobothria (figs. 89, 268, 301, 514, 549, 609, 646); cymbium ovoid in dorsal view, completely fused with bulb, no seam visible, not extending beyond distal tip of bulb, plumose setae absent, without stout setae, without distal patch of setae; bulb elongated, 1–1.5 times as long as cymbium, stout; embolus dark, prolateral excavation absent. Female genitalia often (but not always) with globose, tentlike anterior receptaculum (sometimes apparently enlarged, membranous), often (but not always) with obvious apodemes.

DISTRIBUTION: Known only from Ecuador and adjacent parts of southern Colombia and northern Peru; although most of the species are from sites on either the western or eastern slopes of the Andes, at elevations as high as 3685 m, a few occur at elevations as low as 216 m, in the Amazonian portions of Ecuador.