Rhaucus robustus ( Mello-Leitão, 1941 ) García & Kury, 2017

García, Andrés F. & Kury, Adriano B., 2017, Taxonomic revision of the Andean harvestman genus Rhaucus Simon, 1879 (Arachnida, Opiliones, Cosmetidae), Zootaxa 4338 (3), pp. 401-440 : 422-426

Rhaucus robustus ( Mello-Leitão, 1941) comb. nov.

( Figs 1c , 12–14 , 18d , 23 )

Megarhaucus robustus Mello-Leitão, 1941: 169 , fig. 4; Kury, 2003: 67.

Type material. Holotype ♀ ( MNRJ 150 ), Colombia, Boyacá, La Uvita, examined.

Distribution and habitat. COLOMBIA, Boyacá Department: La Uvita, Tipacoque. Santander Department: Cerrito, Carcasí, Guaca. Between 2850 and 3585 m a.s.l., in Magdalena Valley montane forests ecoregion and Northern Andean páramos. It is the northernmost species of the genus ( Fig. 23 ).

Diagnosis. DS weakly granulated ( Fig. 13a ; contrasting with all other species of Rhaucus ); reticulated pattern of yellow blots only along lateral margins of DS (contrasting with R. serripes that exhibits blots all over the DS), without transverse lines ( Figs 12a , 13a ; contrasting with R. vulneratus , R. quinquelineatus and R. florezi sp. nov.); spines in area III conical and dome-shaped ( Fig. 12c ; differing from R. serripes that exhibits more robust and granular spines).

Redescription. Male (ICN-AO-1161).

Measurements: CL=2.3, CW=5, AL=4, AW=5.6, BaCh=1, FeL III=5.5, FeL IV=7.5, TiL III=3.7, TiL IV=5. Intraespecific variation of body and appendages measurements in Table 1.

Dorsum ( Figs 12a, 12c , 13a–b , 18d ): Dorsal scutum alpha type, weakly granulate ( Fig. 12a ), with blots that resemble a reticle and reach the sides of ocularium and extend toscutal area III ( Figs 12a , 18d ). Abdominal scutum widest at level of groove II; areas I–II mostly smooth, III–IV with some granules. Carapace with some granules on the anterior region ( Fig. 12a ). Ocularium low without median depression, armed with a row of granules ( Figs 12c– e , 13a ). Lateral margins of DS smooth on the medial region ( Figs 13a–b ). Mesotergum delimited, divided into four areas: area I with a pair of short paramedian tubercles; area II with a pair of tiny tubercles; area III with a pair of paramedian, domed/mammilliform, coarsely granulated tubercles; area IV with a pair of small paramedian tubercles ( Figs 12c , 13a–b ). Posterior border of scutum sub-straight and with a row of tubercles. Free tergites I–III with a row of tubercles ( Figs 13a–b ).

Venter ( Figs 12b ): Stigmatic area with a few granules. Stigmata large, oval and transverse. Coxa I with two parallel rows of fused tubercles increasing size distally and with an anterior smooth space for pedipalps to rest; coxa II longer than coxa I, granulate; coxa III longer than I and II, granulate, with posterior margin sigmoid; coxa IV strongly backward, granulate. Genital operculum slightly granulate.

Pedipalps ( Figs 14a–c ): Coxa dorsally and ventrally with one meso-distal granule. Trochanter with one dorsal short tubercle and one ventral tubercle; femur compressed, dorsally with a row of aligned setiferous tubercles of different sizes –not reaching the distal portion– and ventrally the same, slightly more separated from one another (the three/four basal-most setiferous tubercles fused). Patella distally depressed with some dorsal granules; tibia depressed, spoon-shaped, dorsally with some granules, with lateral borders tuberculate and some spiniferous tubercles at distal portion; inner surface slightly striated ( Fig. 14b ). Tarsus long, conical, with some dorsal granules and ventrally with two rows of thickened setae ( Fig. 14c ).

Chelicera ( Figs 12 , 13a–b , 14d–f ): Chelicera very swollen. Basichelicerite rectangular, with a few dispersed granules, the proximal border with some separated medial tubercles and the anterior border smooth, ectal face with one large proximal tubercle and a group of three distal tubercles, the larger one with three irregularly shaped tips, mesal face with some small granules ( Figs 14d–e ). Hand with one tubercle near the joint of the movable finger. Fixed finger slightly curved with the inner surface finely grooved. Movable finger with one conical, sub-basal tooth and with the inner surface at distal portion dentate ( Fig. 14f ).

Legs ( Figs 13c–e ): Coxae I–II dorsally with one anterior and one posterior process; coxa III with one proximal retrolateral tubercle; coxa IV granulate, with a prominent anterolateral clavi inguines and with a posterolateral multicapitate apophysis ( Fig. 13a ). Trochanters I–IV dorsally with some minute granules and ventrally with some tubercles; trochanter III with some large tubercles at retrolateral face ( Fig. 13d ); trochanter IV more granulate than III, with groups of small tubercles visible in retrolateral ventral view ( Fig. 13e ). Femora I–IV sigmoid, very granular; III–IV, dorsally densely granulate, ventrally with two longitudinal rows of triangular tubercles along the entire length, and one retrolateral row of tubercles, increasing in size distally: in femur III the distal-most tubercles of the prolateral side are thinner and curved than those of femur IV ( Figs 13d–e ). Patellae I–IV dorsally very granulate, curved; patellae III–IV with large tubercles in the distal border ventrally very granulate and with one or two tubercles in the retrolateral vental side. Tibiae I–IV granulate; tibiae III–IV very curved, with two longitudinal rows of tubercles –of different sizes and shapes– very close together along the entire length (in tibia IV the distal tubercles are grouped and some are fused or paddle shaped) ( Figs 13d–e ). Metatarsus I–IV with one ventrodistal seta. Tarsi I–II with one smooth claw; tarsi III–IV with 2 subparallel smooth claws and tarsal process ( Fig. 13c ). Tarsal counts: 6(3)–6(3)/15(3)–14(3)/10–10/?–11. Intraspecific variations in Table 2.

Color (in ethanol): Carapace Dark Reddish Brown (44), reticulated in the ocularium. Blots in carapace Brilliant Greenish Yellow (98). Pedipalps, coxae I–IV, free tergites and chelicerae Strong Reddish Brown (40). Trochanters I–IV and legs I–II Strong Yellowish Brown (74). Legs III–IV Strong Reddish Brown (40).

Male genitalia ( Figs 14g –j ): VP of penis subrectangular with slightly concave distal border; VP with two lateral, elongated, dense patches of type 4 microsetae, separated by a longitudinal space in between ( Fig. 14i ). VP with two apical MS C curved and laterally inserted; two MS D, the most distal large and straight, following the same lateral row as MS C, and the other smaller, inserted dorso-laterally on the middle third of VP ( Figs 14g –h ); two MS A straight and laterally inserted, near D2 ( Fig. 14g ); two small MS E volcano-shaped on the ventral face; one small MS B volcano-shaped inserted laterally at the base of the VP ( Fig. 14i ). Glans mostly smooth; stylus long, wattle barbels long ( Fig. 14j ), finger-like process acuminated, enlarged ( Fig. 14g ).

Female. Similar to male, but differs by having carapace at areas I–IV level more globose; anterior part of carapace narrower and coda divergent; tubercles of all scutal areas shorter; legs III–IV thinner than male; tubercles in ventral rows of legs III–IV smaller; chelicerae not hyperthelic ( Figs 12d–e ).

Other material examined. 3 specimens (1 male, 2 females) in 3 lots. COLOMBIA: Boyacá Department: Tipacoque, 1♂ (ICN-AO-1161), Vereda La Calera [06°23'N 72°43'W], 2850 m, 2.ii.2013, N. Beltran leg . Santander Department: Cerrito, 2♀ (IAvH-3000166/IAvH-I-12), Vereda El Mortiño, Parada El Almorzadero [6°19'N 72°33'W] (and not 07°56'N 72°45'W as in the original label), 3585 m, 25.ii.1999, E. González & A. Pulido leg.

Examined by photograph: 1♂ 1♀ ( CBUP-I), Santander Department: Carcasí [6°37'N 72°37'W], 2900 m, under rocks, C. Ríos-Malaver leg. ; Guaca, 1♂ [6.914077 -72.756683], 3200 m, J. Uribe leg.

Figures

FIGURE 1. Photographs of live males of Rhaucus. a – b, Rhaucus vulneratus: a. Showing the five transverse orange lines on DS, b. Morph without transverse lines on DS, c. Rhaucus robustus, d. Rhaucus quinquelineatus, e. Rhaucus florezi sp. nov., f. Rhaucus serripes. [Photographs by A. García (a, b, d) and courtesy of John Uribe (c) and Miguel Medrano (e – f)].

FIGURE 12. Rhaucus robustus (ICN-AO- 1161). Habitus: a – d, male, a. Dorsal view, b. Ventral view, c. Frontal view, d. Lateral view. e. Female, lateral view. Scale bars = 1 mm.

FIGURE 13. Rhaucus robustus (ICN-AO- 1161). Male: a. Dorsal view, b. Lateral view, c. Tarsus I – IV, d. Leg III: dorsal, ventral and retrolateral view, e. Leg IV: dorsal, ventral and retrolateral view. Scale bars = 1 mm.

FIGURE 14. Rhaucus robustus SEM (ICN-AO- 1161). Male: a – c, pedipalp: a. Ectal view, b. Mesal view, c. Tarsus. d – f, chelicera, d. Basichelicerite, dorso-mesal view, e. Dorso-ectal view, f. Fingers, ectal view. g – j, penis: g. Lateral view, h. Dorsal view, i. Ventral view, j. Stylus, apical view.

FIGURE 18. Intraspecific variation of pattern of yellow markings on DS of Rhaucus spp.: a. Rhaucus vulneratus, b. Rhaucus quinquelineatus, c. Rhaucus serripes, d. Rhaucus robustus, e. Rhaucus florezi sp. nov.

FIGURE 23. Central Colombia, showing the geographic distribution of Rhaucus florezi sp. nov., Rhaucus serripes and Rhaucus robustus. Shaded areas in the background are WWF ecoregions. Abbreviations: NAP = Northern Andean Páramo; COMF = Cordillera Oriental Montane Forests; MVMF = Magdalena Valley Montane Forests. Solid red lines: administrative boundaries.