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

publication ID

https://doi.org/10.11646/zootaxa.4338.3.1

publication LSID

lsid:zoobank.org:pub:0D53EB9D-2D0B-4438-851B-A98563D16DCC

persistent identifier

http://treatment.plazi.org/id/546E685E-9F1E-A60D-9493-7EED2598F965

treatment provided by

Plazi

scientific name

Rhaucus robustus ( Mello-Leitão, 1941 )
status

comb. nov.

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

( Figs 1c View FIGURE 1 , 12–14 View FIGURE 12 View FIGURE 13 View FIGURE 14 , 18d View FIGURE 18 , 23 View FIGURE 23 )

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

Type material. Holotype ♀ ( MNRJ 150 View Materials ), 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 View FIGURE 23 ).

Diagnosis. DS weakly granulated ( Fig. 13a View FIGURE 13 ; 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 View FIGURE 12 , 13a View FIGURE 13 ; contrasting with R. vulneratus   , R. quinquelineatus   and R. florezi   sp. nov.); spines in area III conical and dome-shaped ( Fig. 12c View FIGURE 12 ; 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 View FIGURE 12 , 13a –b View FIGURE 13 , 18d View FIGURE 18 ): Dorsal scutum alpha   type, weakly granulate ( Fig. 12a View FIGURE 12 ), with blots that resemble a reticle and reach the sides of ocularium and extend toscutal area III ( Figs 12a View FIGURE 12 , 18d View FIGURE 18 ). 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 View FIGURE 12 ). Ocularium low without median depression, armed with a row of granules ( Figs 12c – e View FIGURE 12 , 13a View FIGURE 13 ). Lateral margins of DS smooth on the medial region ( Figs 13a –b View FIGURE 13 ). 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 View FIGURE 12 , 13a –b View FIGURE 13 ). Posterior border of scutum sub-straight and with a row of tubercles. Free tergites I –III with a row of tubercles ( Figs 13a –b View FIGURE 13 ).

Venter ( Figs 12b View FIGURE 12 ): 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 View FIGURE 14 ): 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 View FIGURE 14 ). Tarsus long, conical, with some dorsal granules and ventrally with two rows of thickened setae ( Fig. 14c View FIGURE 14 ).

Chelicera ( Figs 12 View FIGURE 12 , 13a –b View FIGURE 13 , 14d –f View FIGURE 14 ): 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 View FIGURE 14 ). 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 View FIGURE 14 ).

Legs ( Figs 13c –e View FIGURE 13 ): 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 View FIGURE 13 ). Trochanters I –IV dorsally with some minute granules and ventrally with some tubercles; trochanter III with some large tubercles at retrolateral face ( Fig. 13d View FIGURE 13 ); trochanter IV more granulate than III, with groups of small tubercles visible in retrolateral ventral view ( Fig. 13e View FIGURE 13 ). 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 View FIGURE 13 ). 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 View FIGURE 13 ). 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 View FIGURE 13 ). 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 View FIGURE 14 ): 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 View FIGURE 14 ). 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 View FIGURE 14 ); two MS A straight and laterally inserted, near D2 ( Fig. 14g View FIGURE 14 ); 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 View FIGURE 14 ). Glans mostly smooth; stylus long, wattle barbels long ( Fig. 14j View FIGURE 14 ), finger-like process acuminated, enlarged ( Fig. 14g View FIGURE 14 ).

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 View FIGURE 12 ).

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 GoogleMaps   . 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. GoogleMaps  

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

Kingdom

Animalia

Phylum

Arthropoda

Class

Arachnida

Order

Opiliones

Family

Cosmetidae

Genus

Rhaucus

Loc

Rhaucus robustus ( Mello-Leitão, 1941 )

García, Andrés F. & Kury, Adriano B. 2017
2017
Loc

Megarhaucus robustus Mello-Leitão, 1941 : 169

Kury 2003: 67
Mello-Leitao 1941: 169
1941