Acrographinotus tariquiae, Acosta, 2024

Acosta, Luis E., 2024, The two southernmost species of the Andean genus Acrographinotus Holmgren (Arachnida, Opiliones, Gonyleptidae) described from Bolivia and Argentina, Zootaxa 5481 (5), pp. 547-562 : 552-555

Acrographinotus tariquiae sp. nov.

urn:lsid:zoobank.org:act:58394B7D-EFC6-4DC9-A945-098BB5D75101

Figs. 3A–J , 4A–C

Acrographinotus [sp. from Tarija, S Bolivia] Acosta 2001: 58, 60.

Type series. BOLIVIA, Tarija Department. HOlOtYpe ♂ ( CBF), 3 ♂, 3 ♀, 1 juv. paRatYpes ( CBF), 1 ♂ paRatYpe ( MACN-AR 9597 ), 1 ♀ paRatYpe ( MACN-AR 9598 ), 2 ♂ paRatYpes ( CDA 000.914 ): Subida de La EscaleRa, TaRiquía Flora and Fauna National Reserve , 11–13 December 1995, P. Goloboff leg.— 1 ♂, 1 ♀ paRatYpes ( CBF): AbRa de La Hondura [ca. 21°59.492’S 64°37.296’W], 2700 m a.s.l., 10 December 1995, P. Goloboff leg.

Type locality. Subida de La Escalera (ca. 22°0.969’S 64°34.690’W, ~ 2000–2300 m), Tariquía Flora and Fauna National Reserve, Tarija Department, Bolivia .

Etymology. The name tariquiae is formed as the feminine genitive of the Bolivian protected area where the type locality is placed (Tariquía Reserve).

Description. Measurements and meristics. DS length: males 5.9–7.2 mm (mean 6.4 mm, n=8), females 6.3–7.4 mm (mean 6.8 mm, n=5). FeIV/DS ratio (males): 0.86–1.15 (mean 1.02, n=8); in 5/ 8 males this ratio is above 1, in 7/8 above 0.9 ( Fig. 2 ). Detailed measurements of the holotype male and a female paratype: Table 1 . Tarsal formula: males 5–6:8–10:7:7 (holotype with 5/6:9:7:7), females 6:7–9:7:7.

Coloration in ethanol 70%. General color uniform dark hazel, with chelicera, pedipalps, legs I–III and metatarsus IV yellowish; weak pigment reticles insinuate on DS and appendages.

Males (α): Dorsum. DS tYpe λ (lambda, cOda shORt, caRapace with subpaRallel sides; Fig. 3A ), unaRmed, granulation feeble. Anterior border of carapace smooth, frontal hump negligible. Ocular mound low, with a small median apophysis ( Fig. 3F ); in some specimens the ocular mound is completely unarmed or has a median notch. DS area I divided, areas I–IV entire; practically smooth except for sparse small granules insinuating a row on areas I–IV and lateral areas, better defined on area V and free tergites I–II. FT-III with a strong median apophysis, slightly sigmoid in lateral view, and a row of small inconspicuous granules each side.

Venter. Posterior margin of stigmatic segment gently concave; free sternites nearly smooth, with row of minute granules. VAP armed by two strong apophyses that flank a ‘shelf-like’ projection in between; the anus is thereby ‘armored’ by three apophyses, one dorsal (FT-III) and two ventral ( Figs. 3B–D ).

Chelicerae. Tegument tenuously rugose, bulla unarmed.

Pedipalps. Weak, dorsal tegument finely rugous; blunt ventral setigerous tubercles on trochanter and femur; no medial subapical spine on femur. Pedipalp spination: LAT: Ti i_[Ii•], Ta IiIi – MED: Ti IiIi, Ta IIi.

Legs I–III. Unarmed, all segments with tegument finely granulous.

Leg IV. Coxa IV smooth, dilated and with a short, blunt prolateral apophysis, diagonal, and a small retrolateral one, better discernible from ventral. Coxa-trochanter joint slightly oblique in ventral view ( Fig. 3B ).

Trochanter IV wide, subtrapezoidal and asymmetric (retrolateral side larger than prolateral one), obliquely articulated to the sides; one blunt, tuberous prodorsal mound near the apical border, opposite to the coxal apophysis; distal margin with a pair of small acute retrodorsal apophyses.

Femur IV sub-straight, diagonally diverging by around 25° ( Figs. 3A–B ), with subdistal narrowing and apical end slightly widened; longitudinal rows of granules to small apophyses, the most conspicuous being the retrodorsal row, formed by truncate tubercles, which, beyond the subdistal narrowing, ends in a large conic subapical apophysis and a small apical one ( Figs. 3A, E ); dorsal row of spaced 8–9 tubercles, those in the middle larger; pro- and retrolateral rows of sparse rounded granules; pro- and retroventral incomplete rows of small acute granules ending in small unciform apophyses.

Patella IV granulous, with 2–3 acute ventral tubercles.

Tibia IV with rows of small acute granules, they are progressively larger on the retroventral row, ending distally as small apophyses.

Penis ( Figs. 4A–C ). Distal end slightly higher than wide; front margin of VP almost straight, lateral sides gently concave. Basal macrosetae (A1–A3 + B) arranged in a transversal row, at about the same level of the truncus-glans joint. Stylus tip straight and slightly dilated; VPS with the generic ‘ibis head with crest’ shape, ‘beak-like’ process curved and subtle ‘veins’ perceptible through the translucid membranous expansion.

β males: TwO specimens (Out Of eight) shOw decided feminized featuRes and aRe cOnsideRed β males. In them, VAP armature is rudimentary: apophyses are replaced by button-like tubercles and there is no ‘shelf’ ( Figs. 3I–J ). In addition, slenderness, granulation and curvature of FeIV look much like in females, and there is no subapical narrowing. Noteworthily, these males are not the smallest ones in the sample (both are above the mean DS length; Fig. 2 ). The best exteRnal featuRe tO disceRn them fROm females is the DS shape, which Remains λ- tYpe as in α-males. FOR additiOnal details On β males, see the cOmpaRisOn sectiOn Of A. calilegua sp. nov. below.

Females: DS tYpe α-K (alpha-keYhOle, cOda mOdeRatelY lOng with diveRgent sides), unaRmed, slightlY laRgeR than males ( Fig. 2 ) and more slender than A. calilegua sp. nov. Granulation slightly more conspicuous and ocular mound higher than males. On free tergites granules are more acute, especially on FT-III, which also bears a small median apophysis, either horizontal or slightly oblique (inclination likely depends on the abdominal swelling). Margin of VAP bordered by small granules, no vestige of male armature. Coxa IV with small acute prolateral apophysis. Trochanter IV: one pair of acute retrolateral granules. FeIV slender, slightly curved at its base, then sub-straight, with rows of granules; retroapical apophysis very small, pointing backwards.

Variability. Except fOR β-tYpe specimens, VAP Of males alwaYs has a ‘shelf’, with laRge-acute apOphYses in 3/ 8 males, laRge-blunt in 2/8; in a single male (the smallest One, which OtheRwise dOes nOt have a decided β habitus) a quadrangular shelf-like projection with acute angles remains ( Figs. 3G–H ). The apophysis on FT-III is sigmoid in lateral view in 5/ 8 males, straight or curved in the rest. The diagonal articulation of leg IV is more exaggerated in larger males. In both sexes the low apophysis on the ocular mound may vanish, leaving a plain mound, even with a median notch giving an odd paired appearance.

Comparisons and diagnosis. In general habitus and the armature of leg IV of male, A. tariquiae sp. nov. resembles the type species A. erectispina , the latter being larger (DS length 7.1–9.2 mm vs 5.9–7.2 mm in A. tariquiae sp. nov.); in some features (but not in the overall appearance), the new species can also be compared to A. niawpaq . Of the three, A. tariquiae sp. nov. has the most gracile look, with weaker development of apophyses and granulation. The presence of large grains—almost small tubercles—on the DS of A. erectispina is an easily observable difference (DS of A. tariquiae sp. nov. nearly smooth, with tiny granules in A. niawpaq ). VAP is armed in all three, but while the apophyses remain independent in A. erectispina , they delimit a kind of ventral ‘shelf’ in A. tariquiae and A. niawpaq ( Fig. 3B , see also Acosta 2001: figs. 2, 25). Further, the apophysis of FT-III is subhorizontal in Roewer’s species, sigmoid in A. tariquiae and A. niawpaq (much more developed in the latter). Acrographinotus erectispina bears one single large retroapical apophysis on trochanter IV, whilst in A. tariquiae sp. nov. and A. niawpaq there are two short apophyses; the bilobated prodorsal apophysis is peculiar to A. niawpaq (it is simple in the others). The retrodorsal row of truncate tubercles on FeIV is similar in A. erectispina and A. tariquiae , whereas in A. niawpaq the dorsal apophyses are larger, and the femur is thicker. The subdistal narrowing of FeIV is evident in A. tariquiae and A. niawpaq , not as much in A. erectispina (cf. Acosta 2001). As evident in the identification key, VAP enables an easy separation of A. tariquiae sp. nov. from other members of the genus: it is unarmed in the ‘spiny-looking’ species ( A. curvispina . A. mitmaj , A. ortizi ) and bears large divergent apophyses in A. ceratopygus . Differences with A. calilegua sp. nov. are addressed to in detail below.

Distribution and habitat. At the moment, the species is known from two sites in Tarija Department, southern Bolivia ( Fig. 7A ). The type locality (Subida de La Escalera, ~ 2000–2300 m a.s.l.) is placed on the east-faced slope of the N-S oriented mountains that delimit the Tariquía Flora and Fauna National Reserve. This area is described as having an abrupt relief, with herbaceous vegetation on higher sectors, and shrub- or woodlands of Polylepis, Alnus or Podocarpus at lower elevation and in ravines, nearly rainforest-like formations further below ( Ayarde et al. 1999). The specimens were caught on the steep walls of a stream ravine, in a humid sector with impoverished montane forest that includes arborescent ferns (P. Goloboff in litt.). The second site (Abra de La Hondura, 2700 m a.s.l.), on the west slope of the same range, is more xeric than the former. It has a similar scabrous landscape and is dominated by grasslands, especially on elevated sites; small Polylepis woodlands develop in ravines and more xerophilous vegetation in lower slopes ( Ayarde et al. 1999; P. Goloboff in litt.).

Figures

FIGURE 2. Comparative morphometrics of Acrographinotus tariquiae sp. nov. and A. calilegua sp. nov., displayed as box-plots with data points (internal lines, dashed: mean, solid: median). Left: DS length (in mm) for males and females; the single outlying female from El Duraznillo (star), tentatively assigned to A. calilegua but not used in calculations, is shown for reference. Right: FeIV/DS ratio, males. In box-plots of male A. tariquiae, small aRROws fROm the left identifY the twO examined β-males.

FIGURE 3. Acrographinotus tariquiae sp. nov. A–F: HOlOtYpe ♂ (CBF). A. DORsal scutum, fRee teRgites (alsO shOwing dORsal anal operculum and VAP apophyses), coxae IV, right trochanter and femur IV, dorsal view. B. Venter, with coxae IV, genital and stigmatic segments, free sternites, VAP with apophyses (also showing apophysis of FT-III), right trochanter and femur IV. C. Right coxa, trochanter, femur, patella and tibia IV, prolateral view. D. Detail of free tergites, dorsal and ventral anal operculum, lateral view. E. Right femur and patella IV, retrolateral view. F. Ocular mound, posterior view. G–J: Armature variations on FT-III and VAP in tOpOtYpical ♂ paRatYpes. G–H: Smallest α-male (CBF), I–J: β-male (CDA 000.914). G, I: ventRal view; H, J: lateral view. Scale lines: 2 mm (A–E, G–J), 1 mm (F).

FIGURE 4. Acrographinotus tariquiae sp. nov., distal end Of penis, HOlOtYpe ♂ (CBF). A: dORsal view; B: lateRal view; C: detail of stylus and ventral process. Scale lines: 0.1 mm (A, B), 0.05 mm (C).

FIGURE 7. A: Records of Acrographinotus tariquiae sp. nov. in Tarija Department, Bolivia (yellow dots) and A. calilegua sp. nov. in Jujuy Province, Argentina (red dots); blue contours: protected areas (1: Tariquía Flora and Fauna National Reserve; 2: Calilegua National Park). B: Type locality of A. calilegua sp. nov.: cloud forests at ‘Monolito’ (ca. 1700 m a.s.l.), Calilegua National Park, Jujuy Province, Argentina.