Rumikiru Ojanguren-Affilastro & Mattoni & Ochoa & Prendini 2012, n. gen.
Creators: name: Ojanguren-Affilastro, Andrés A.
name: Mattoni, Camilo I.
name: Ochoa, José A.
name: Prendini, Lorenzo
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Scorpiones
Bothriuridae
Rumikiru

description: Rumikiru, n. gen.
Figures 1–28; table 1
Orobothriurus Ojanguren-Affilastro, 2003a: 117–122 (part); Ojanguren-Affilastro, 2004: 72 (part); Ochoa, 2004: 44 (part); Agusto et al., 2006: 415–419 (part); Rein, 2007: 5 (part); Pizarro-Araya et al., 2008: 270, 271 (part); Vrech et al., 2011: 465, 467, 470, 475, 482 (part).
TYPE SPECIES: Orobothriurus lourencoi Ojanguren-Affilastro, 2003 [= Rumikiru lourencoi (Ojanguren-Affilastro, 2003), n. comb.].
ETYMOLOGY: The indigenous peoples of the Chilean Atacama originally spoke Kakan or Kunza, depending on the region and, after the Inca invasion, added Quechua and Aymara to their languages. Rumikiru is formed from two Quechua words, rumi meaning “stone” and kiru meaning “tooth,” and refers to the large denticles on the movable fingers of the pedipalp chelae in this genus, unique in the family Bothriuridae, and to the habitat of its two species, both of which appear to be restricted to rocky slopes.
DIAGNOSIS: Species of Rumikiru, n. gen., are easily recognized by the enlarged basal denticle of the median denticle row of the pedipalp chela movable finger (figs. 18A, 19A, 24C, 25A, C), which is approximately three times larger than and replaces the first five or six median denticles. Such a hypertrophied basal denticle is unique among bothriurids. An enlarged basal denticle on the movable finger is exhibited by some bothriurids, e.g., Brachistosternus ehrenbergii (Gervais, 1841), but replaces no more than two or three denticles (Ochoa and Ojanguren-Affilastro, 2007). The submedial position of the apophysis on the internal surface of the pedipalp chela manus in the adult male of Rumikiru, n. gen. (figs. 18C, D, 22A, C, D, 24A, B, 25A, B), is also unique in the family. The apophysis is situated in the distal third of the surface in all other bothriurid taxa in which it occurs, and is absent from the pedipalp chela manus of basal bothriurids, e.g., Lisposoma Lawrence, 1928, and Thestylus Simon, 1880 (Prendini, 2000, 2003). The shape of the apophysis and the position of trichobothium ib distal to it are also unique to Rumikiru, n. gen. The new genus may be further separated by a twist in the medial to distal third of the dentate margin of the pedipalp chela fingers, which abruptly alters the orientation of the median denticle row (more conspicuously on the movable finger), in the male (figs. 18A, 22A), that is absent in other bothriurid genera. Additionally, the carapace of Rumikiru, n. gen., is dorsoventrally compressed (fig. 12C, D), unlike many other bothriurids, in which it is more convex.
Rumikiru, n. gen., is most closely related to Pachakutej, based mainly on characters of the hemispermatophore (fig. 10). The two genera share the presence of one sclerotized apophysis on the internal fold of the internal lobe, and a papillose fold in the basal lobe (figs. 10C, H). Species of Pachakutej, however, possess a unique synapomorphy, a spatulate terminal process on the basal lobe of the hemispermatophore (Ochoa, 2004) that is absent in Rumikiru, n. gen., and are markedly more pigmented. The pedipalp carinae are more pronounced, especially on the femur and patella, in Rumikiru, n. gen. (figs. 16, 17, 20, 21), than in Pachakutej. The two genera may also be separated by the trichobothrial pattern of the pedipalp chela manus. Trichobothrium V 2 is situated in the same axis as V 1 and V 3 in Rumikiru, n. gen. (figs. 18C, 19C, 22C, 23C), but not in the same axis, forming an angle less than 180°, in Pachakutej, and Db is equidistant between Dt and Eb 3 in Rumikiru, n. gen. (figs. 18B, 19B, 22B, 23B), but close to Dt in Pachakutej. Finally, the VSM carinae of metasomal segment V are subparallel and situated close to the VL carinae in Rumikiru, n. gen. (fig. 27), whereas the VSM carinae are slightly inclined toward the external margin in the posterior third of the segment, or absent, in Pachakutej.
INCLUDED SPECIES: This genus contains two species: Rumikiru atacama, n. sp., and Rumikiru lourencoi (Ojanguren-Affilastro, 2003), n. comb.
DISTRIBUTION: Rumikiru, n. gen., is endemic to the Atacama Desert of northern Chile (figs. 2, 3, 4A). All known records are located in the Antofagasta Province of Region II (Antofagasta) and the Chañaral and Huasco provinces of Region III (Atacama). The distribution of this genus is allopatric with that of its sister genus, Pachakutej, from the inter-Andean valleys of Peru (fig. 3).
ECOLOGY. In addition to its unusual morphology, Rumikiru, n. gen., occupies an unusual habitat among bothriurid scorpions. Most bothriurids are fossorial, requiring exposed soil to construct burrows. However, all personally collected specimens of Rumikiru, n. gen., were found in rocky habitats, with almost no exposed soil. At Pan de Azúcar National Park, the type locality of R. lourencoi, n. comb., several specimens were captured on vegetationless scree slopes com- prising piles of sharp, loose stones accumu- lated below steep cliff faces. At Llanos de Challe National Park, specimens of R. atac- ama, n. sp., were collected in a slightly more vegetated environment, but this species was common only on scree slopes, cliff faces, and exposed rocky outcrops (fig. 4A).
The environment inhabited by Rumikiru, n. gen., differs markedly from that of its sister genus, Pachakutej, which occurs under stones in more humid habitats, in inter-Andean valleys and montane rainforests on the eastern slopes of the Andes in Peru (Ochoa, 2004).
Rumikiru, n. gen., displays an unusual defensive behavior, not reported among other scorpions, which typically curve the metasoma and strike out with the aculeus and, in some species, the pedipalp chelae, when threatened: males spread the pedipalps wide open, making short pulses or vibrations with them, without curving the metasoma (fig. 4B).
description: Published as part of Ojanguren-Affilastro, Andrés A., Mattoni, Camilo I., Ochoa, José A. & Prendini, Lorenzo, 2012, Rumikiru, n. gen. (Scorpiones: Bothriuridae), a New Scorpion Genus from the Atacama Desert, pp. 1-44 in American Museum Novitates 2012 (3731) on pages 5-11, DOI: 10.1206/3731.2, http://zenodo.org/record/5359990