Two new endemic species of Bistriopelma (Araneae: Theraphosidae) from Peru, including a new remarkable horned tarantula

The spider genus Bistriopelma Kaderka, 2015 is endemic to Peru and includes three species known to date: Bistriopelma lamasi Kaderka, 2015, B. matuskai Kaderka, 2015 and B. titicaca Kaderka, 2017. The present contribution diagnoses, describes and illustrates two new species of Bistriopelma from Peru: B. peyoi sp. nov. and B. kiwicha sp. nov., both based on male and female. The male of B. peyoi sp. nov. is provided with a remarkable thoracic horn, and the species is the first horned tarantula for this genus. An updated distribution map for all known species is presented.


Introduction
The family Theraphosidae Thorell, 1869, known as tarantulas, is the most speciose family among Mygalomorphae Pocock, 1892 and currently contains more than 900 described species according to the World Spider Catalog (2019). They are the largest and heaviest spiders of the world inhabiting almost all terrestrial ecosystems, with the exception of polar areas. The highest abundance and diversity are registered for tropical, subtropical, semi-arid and arid regions. They can be found from sea level to about 4500 meters a.s.l. and some can be found living deep inside caves. Inside this family, eleven subfamilies are recognized, Theraphosinae Thorell, 1870 being the most diverse, with more than 60 genera (World Spider Catalog 2019). This monophyletic group is characterized by the presence of urticating setae of type III, a male palpal bulb with the subtegulum extended over the tegulum, the embolus with keels, and the presence of tarsal clavate trichobothria in a straight row (Pérez-Miles et al. 1996;Guadanucci 2014).
The genus Bistriopelma  belongs to the subfamily Theraphosinae. Its representatives are characterized by the presence of two abdominal dorsolateral patches of the type III urticating setae. Females are recognized by the spermathecae composed of two subparallel receptacula terminated with transverse oval lobes. Males are characterized by the aspect of the bulb, with a long and sigmoid curved embolus provided with two prolateral keels (prolateral superior and inferior) . Bistriopelma was originally established by  with two species from the Andean region in Peru. In this work, Bistriopelma lamasi  was described as the type species of the genus, based on male and female from Ayacucho, Peru. Bistriopelma matuskai  was described from Apurimac, Peru, based only on females. Later, Kaderka (2017) described the male of B. matuskai and the new species, B. titicaca Kaderka, 2017, from Puno, Pucará, based on both sexes.
During examination of material deposited at the Museo de Biodiversidad del Perú, two new species of Bistriopelma were discovered and are, herein, described and illustrated. One of them includes a new remarkable horned tarantula that now represents the record of another theraphosid genus with this rare morphological feature.

Material and methods
The material examined in the present study is deposited in the Museo de Biodiversidad del Perú, Cusco, Peru (MUBI), Curator José A. Ochoa.
All measurements are in millimeters. Total length was taken from the dorsal view and does not include the chelicera and spinnerets. Carapace length was measured from the clypeus margin to the posterior margin. Palp and leg segments were measured between the joints in dorsal view: femur, patella, tibia, metatarsus and tarsus. The length and width of the carapace, eye tubercle, labium and sternum are the maximum values obtained. Legs measurements were taken with a digital caliper to the nearest 0.001 mm and other measurements and photographs were obtained with a Zeiss Stemi 305 stereo microscope, Zeiss AxioCam, and ZEN Imaging software ver. 1.0. Terminology for tibial apophyses (or spurs) follows the general usage in Theraphosidae and it includes the two branches (e.g., Bertani 2001;Pérez-Miles et al. 2008). Male palpal bulb keel terminology follows Bertani (2000). The extent of tarsal and metatarsal scopulae on ventral side of both leg segments was expressed as a proportion of the total length of segment, from apical end. The leg spination was described for each leg segment into the four quadrants (ventral, prolateral, retrolateral and dorsal) and each quadrant described separately from basal to apical section (modifi ed from Petrunkevitch 1925;Kaderka , 2017. Urticating setae terminology follows Cooke et al. (1972) and Bertani & Guadanucci (2013).  In addition, females can be distinguished from the other known species by the spermathecal receptacles with large granules pointing outwards (Fig. 7).

Etymology
The specifi c epithet is a patronym in honor of the Belgian cartoonist Pierre Culliford , mostly known by his pseudonym ʻPeyoʼ, who created the comic strip ʻThe Smurfsʼ. The type locality of this new species is located near the Pampachiri Stone Forest, which is known as Smurf's house because European Journal of Taxonomy 644: 1-20 (2020) of the conical rock formations. Moreover, the prominent projection of the cephalic region of the male resembles the shape of the Smurfs' hats. . Live specimens: Carapace dark covered with long yellow setae giving a ʻgoldenʼ aspect; abdomen black dorsally covered with long red hairs mainly on proximal region and on patches of urticating setae; spinnerets black; legs dark with pale yellow hairs mainly on femora, patellae and tibiae ( Fig. 1). In ethanol: carapace reddish brown covered with long yellow setae giving a ʻgoldenʼ aspect mainly on cephalic region, central thoracic region and carapace margins; abdomen black covered with long pale setae and patch of long yellow setae on dorsal apical region with two dorsolateral patches of urticating setae, ventrally black with book lung markings and region above epigastric furrow light brown, spinnerets black; legs brown covered with pale setae, labium and maxillae yellowish brown, sternum brown (Fig. 2). . Total length, without chelicerae and spinnerets: 18.89. Carapace: length 8.87, width 8.59. Abdomen: length 9.22. Eye tubercle: length 1.19, width 1.52. Eyes sizes and interdistances: AME 0.17, ALE 0.38, PME 0.16, PLE 0.39, AME-AME 0.37, AME-ALE 0.16, PME-PME 0.70, PME-PLE 0.09, ALE-PLE 0.21. Labium: length 1.46, width 1.25. Sternum: length 4.09, width 3.91. Length of legs and palpal segments in Table 1. C

L
. Leg formula: I ˃ IV ˃ II ˃ III. All paired tarsal claws with 3-4 ventral teeth on each. Scopulae: Ventrally all tarsi fully scopulated. Tarsi I and II entire, III and IV divided by band of setae. Metatarsus I ⅓ scopulated, II ½ scopulated, III ½ scopulated, IV ⅓ scopulated. Dorsal face of all tarsi with two longitudinal rows of claviform trichobothria. Tibia I two-branched tibial apophysis: ventral branch with single strong apical spine and prolateral branch with single inner strong spine, of same length as branch (Fig. 3C-D). Metatarsus I contacts apex of ventral branch of tibial apophysis when fl exed (Fig. 3C). Palps with cymbial lobes almost equal in sizes covered with long setae (Fig. 3A-B). Tibia tapering to the apex.

P
. Bulb with narrow embolus projecting retrolaterally from tegulum, sigmoidly curved, and two close subparallel smooth keels, PS and PI ( Fig. 4A-B). Tegulum with short triangular basal projection (Fig. 4A). . Live specimen: Carapace dark covered with long yellow setae giving a ʻgoldenʼ aspect mainly on cephalic region and margins; abdomen black dorsally covered with long red hairs mainly on proximal region and on patches of urticating setae; spinnerets black; legs dark with reddish hairs mainly ventrally on femora, patellae and tibiae ( Fig. 5A-B). In ethanol: Carapace brown covered with long yellow setae giving a ʻgoldenʼ aspect mainly on cephalic region and carapace margins; abdomen black covered with long pale setae and patch of long yellow setae on dorsal apical region with two dorsolateral patches of urticating setae, spinnerets black; legs and sternum ventrally dark brown; labium and maxillae reddish brown (Fig. 6).

S
. Two separated seminal receptacles with large granules, each distally ended with oval lobe pointing outwards without ventral projections (Fig. 7).

Distribution and natural history
Bistriopelma peyoi sp. nov. is known from Pampachiri and Ayamachai (Figs 5C, 14), Department Apurimac, Peru, at elevations from 3861 to 4027 m a.s.l, and both are separated by 37 km in a straight line. Specimens were collected during the rainy season (December), under rocks, between bushes and rocky areas (Fig. 5C). This species inhabits high Andean puna, where most of the area was covered by pasturelands and introduced pine trees. Throughout the area we could fi nd small villages, farming, and grazing activities of cows and sheep. diff er from B. lamasi by the absence of a dark pubescence on ventral maxillae (Fig. 12F-G) and from B. titicaca by the absence of spiniform setae on prolateral faces of coxae I-IV (Fig. 12F). In addition, the two fi ne-grained separated seminal receptacles of B. kiwicha sp. nov. resemble those of B. matuskai and B. titicaca, but diff er from them by the shorter ducts and absence of ventral projections (Fig. 13).

Etymology
The specifi c epithet, kiwicha, is a Quechua word referring to Amaranthus caudatus L., a plant widely cultivated in the Peruvian Andes, particularly in the district of San Salvador, where this new species was found. It has been used in the form of cereals or fl our from the plant's seeds for more than 1400 years and was included in the daily diet during the Inca civilization.

Description
Male (holotype, MUBI 12) C . In ethanol: Carapace reddish brown with dark short setae on cephalic region between the fovea and eyes covered with yellow setae around eye tubercle and carapace margins; abdomen black with two patches of long yellow setae on dorsal apical region on dorsolateral patches of urticating setae, ventrally dark brown with book lung markings and region above epigastric furrow light brown, spinnerets brown; legs brown, labium and maxillae yellowish brown, sternum brown (Fig. 8).

L
. Leg formula: I ˃ II ˃ IV ˃ III. All paired tarsal claws with 3-4 ventral teeth on each. Scopulae: Ventrally all tarsi fully scopulated. Tarsi I and II entire, III and IV divided by band of setae. Metatarsus I and II fully scopulated, III ¾ scopulated, IV ½ scopulated. Dorsal face of all tarsi with two longitudinal rows of claviform trichobothria. Tibia I two-branched tibial apophysis: ventral branch with single strong apical spine and spiniform setae on inner side and prolateral branch with single inner strong spine, shorter than the branch. Metatarsus I contacts apex of ventral branch of tibial apophysis when fl exed (Fig. 9C-E). Palps with cymbial lobes almost equal in sizes covered with long setae (Fig. 9A-B). Palpal tibia tapering to the apex.
Female (paratype, MUBI 41) C . Live specimen: Carapace dark brown with reddish setae on margins; abdomen black with few red setae on proximal region and on dorsolateral patches of urticating setae; legs dark brown with reddish setae ventrally (Fig. 11A). In ethanol: Carapace light brown with pale setae on carapace margins; abdomen dark brown with two small dorsolateral patches of urticating setae, spinnerets brown; legs and sternum ventrally dark brown, labium and maxillae reddish brown (Fig. 12).

L
. Leg formula: I ˃ IV ˃ II ˃ III. All paired tarsal claws with 2-4 ventral teeth on each. Scopulae: Ventrally all tarsi fully scopulated, palp and leg I entire, legs II-IV divided by a band of setae. Metatarsi I ¾ scopulated, II ½ scopulated, III ⅓ scopulated, IV ¼ scopulated. Dorsal face of all tarsi with two longitudinal rows of claviform trichobothria.

Distribution and natural history
record for the genus. The typical habitat of the species described in the present work comprises shrub vegetation in the inter-Andean valleys and mountain grass slopes (Figs 5C, 11B-C) covered with stones under which spiders construct their burrows, similar to that found for the other species of Bistriopelma .
The new species of Bistriopelma described here, B. peyoi sp. nov., is remarkable not only because of the foveal protuberance of the male but also by the absence of a fovea in the females. As far as we know, this is the fi rst species with sexual dimorphism for the cephalic projection. The only approach of the function of the foveal protuberance or ʻhornʼ was made by West (1986) studying African Ceratogyrus Pocock, 1897 specimens. This author assumed that there may be two primary functions of the foveal horn: fi rst, to serve as an attachment site for the prominent muscles of the prosoma, mainly those attached to the sucking stomach; and second, to accommodate the expansion of the midgut diverticula for food storage (West 1986). However, for this species, dissection of specimens should be done in order to see which internal organs are inside the foveal horn space to examine whether its function is similar to that in Ceratogyrus, in particular because one species is from a somewhat hot xeric habitat and the other species from a cold xeric habitat. The discovery of this morphological feature in Bistriopelma led to four Neotropical genera of Theraphosinae that possess this remarkable character. Members of the other theraphosid genera from the Neotropics that also have similar foveal structures are Cyrtopholis Simon, 1892 (Caribbean), Sphaerobothria Karsch, 1879 (Costa Rica and Panama) and Umbyquyra Gargiulo, Brescovit & Lucas, 2018 (Bolivia and Brazil). The other known genus of Theraphosidae that have a similar feature is the African Ceratogyrus (De Wet & Dippenaar-Schoeman 1991; Peters 2000) as mentioned above. Recently, the new remarkable species C. attonitifer Engelbrecht, 2019 was described having a uniquely long soft protuberance (Midgley & Engelbrecht 2019). However, the foveal protuberance found in the genus Bistriopelma is fully sclerotized, similar to that of all other genera where it is known to occur.
Unfortunately, this character is highly variable among species and now also appears to be variable among sexes. These structures range from almost absent to protruding projections on the back of the carapace (De Wet & Dippenaar-Schoeman 1991; Gargiulo et al. 2018;Midgley & Engelbrecht 2019) and their homology has not yet been studied among the various occurrences in Theraphosidae. It can thus hardly be used as diagnostic for some genera and should be treated as homoplastic, appearing as a convergence in a few species of Theraphosidae (Gallon 2001).
The discovery of these two new species highlights the relevance of inventories and taxonomic work yet to be carried out in Peru. In this way, this contribution is part of many future works that authors are conducting to describe the great theraphosid diversity found in Peru.