Ibotyporanga Mello-Leitao 1944
Creators: name: Huber, Bernhard A.
name: Meng, Guanliang
name: Král, Jiří
name: Ávila Herrera, Ivalú M.
name: Carvalho, Leonardo S.
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Araneae
Pholcidae
Ibotyporanga

description: Genus Ibotyporanga Mello-Leitão, 1944
Ibotyporanga Mello-Leitão, 1944: 6. Type species: I. naideae Mello-Leitão, 1944.
Ibotyporanga – Huber 2000: 94. — Huber & Brescovit 2003: 17. — Huber & Villarreal 2020: 62.
Diagnosis
Small short-legged pholcids with eight eyes and globular abdomen (Figs 25, 55, 73), similar in size and body shape to other New World Ninetinae in the genera Pholcophora, Papiamenta Huber, 2000, and Gertschiola Brignoli, 1981. Males are easily distinguished from these and from all other pholcids by single median process on chelicerae (e.g., Figs 29, 34, 40). Corresponding pockets on female epigyna (e.g., Figs 30, 35, 41) are diagnostic for females, but less unique among Pholcidae (similar median pockets occur in other subfamilies, e.g., in Mesabolivar). Males further distinguished by unique light prolateral band of unknown function on procursus (e.g., Figs 28, 33, 37).
Description
Male
MEASUREMENTS. Total body length 1.5–2.7; carapace width 0.6–1.0. PME diameter 50–100 µm; AME diameter 30–80 µm. Leg 1 length 2.8–7.4; tibia 1 length 0.7–2.0; tibia 4 in most species longer than tibia 1, only in the relatively long-legged I. xique sp. nov. and I. xakriaba sp. nov., as well as in I. itatim sp. nov., shorter (tibia 4 / tibia 1 length: 0.94-0.98); leg femora diameters 0.13–0.22; leg tibiae diameters 0.09–0.12. Tibia 1 L/d in most species 8–15, only in the long-legged I. xique and I. xakriaba higher: 20 and 18, respectively.
COLOUR. In ethanol mostly ochre-yellow to light brown, carapace medially and ocular area often darker, legs usually with darker rings on femora (subdistally) and tibiae (proximally and subdistally); abdomen pale gray, usually with darker internal marks dorsally and laterally; ventrally with light ochre to brown plates in front of gonopore and in front of spinnerets. Live specimens often with slightly reddish or orange prosoma and legs.
BODY. Habitus as in Figs 25, 55, and 73. Ocular area slightly raised. Carapace with distinct but shallow thoracic groove (Figs 2–3). Clypeus with sclerotized rim with median notch (Fig. 107A). Sternum slightly wider than long, sometimes with pair of low and indistinct anterior processes near coxae 1 (Fig. 3G); processes without pores. Abdomen globular. Numerous rimmed pores (Fig. 18) at regular intervals on many body parts, especially on legs, but also on chelicerae and abdomen; outer diameter 2.2–4.2 µm; opening diameter: 0.35–0.45 µm. Gonopore with four epiandrous spigots in variable pattern (evenly spaced or in two pairs; Figs 4–5). Spinnerets general arrangement as usual in Pholcidae (Fig. 6); ALS with only two spigots (Figs 7–8): one strongly widened spigot and one long and slender spigot; PMS with two short conical spigots (Figs 6–8); PLS without spigots; AMS area with one or two median hairs and slightly modified sculptured area (Fig. 7A–B).
CHELICERAE. With distinctive median frontal apophysis, usually in proximal position (e.g., Figs 34, 40), only in I. ziruma sp. nov. in distal position (Fig. 29); chelicerae width 0.25–0.40. Stridulatory files (Figs 9–10) very fine and poorly visible in dissecting microscope, with ~45–65 ridges, distances between ridges (in eight species studied with SEM) 1.7–3.1 µm, distances proximally in some species smaller than distally (e.g., I. guanambi sp. nov., I. sertao sp. nov.), in other species proximally larger than distally (e.g., I. naideae Mello-Leitão; I. itatim sp. nov.).
PALPS. Coxa unmodified; trochanter with indistinct ventral protrusion; femur variably long, proximally with retrolateral process sometimes directed towards distal, with prolateral stridulatory pick (modified hair; Fig. 12F), femur distally widened but unmodified; femur-patella joints usually not (or very slightly) shifted toward prolateral side; patella ranging from very short (e.g., Fig. 47) to very long (e.g., Fig. 109); tibia with two trichobothria; tibia-tarsus joints usually slightly shifted toward retrolateral side; palpal tarsal organ capsulate with small opening (Fig. 13), outer diameter 6–10 µm, opening diameter 1.3– 2.5 µm; procursus shape highly variable, from short and wide (e.g., Figs 28, 33, 39) to very long and slender (e.g., Figs 62, 85, 102), always with light prolateral band of unknown function (Figs 28, 33, 37); distally often with tiny side branch (Fig. 12A–C), tip often semi-transparent (Figs 57, 76, 114); in some species with variably long dorsal side branch (e.g., Figs 81, 89, 98); genital bulb with proximal sclerite connecting to tarsus, strongly attached to tendon of muscle from tibia (sclerite thus usually breaks when detaching bulb from palp; therefore often not drawn); bulbous part of genital bulb in most species with distinct prolateral sclerite (e.g., Figs 28, 33, 37), in several species with small ventral tubercles (prominent in I. naideae, Fig. 11E–F); bulbal process with variably complex tip consisting of sclerotized and membranous elements and presumably carrying sperm duct opening.
LEGS. Without spines but with stronger hairs ventrally on all femora (Fig. 15A–B; stronger compared to neighboring leg hairs: diameter ~5 µm versus ~3 µm in neighboring hairs, but similar hairs occur on leg coxae, sternum, palps, carapace, and abdomen). Without curved hairs. Tibia 1 or tibia 1+ tibia 2 with sexually dimorphic short vertical hairs (Fig. 16), in several rows or bands, base diameter 4.1–6.3 µm, length 17–34 µm (usually 17–25 µm), diameter proximally 1.6–2.1 µm, at half-length 0.9–1.0 µm. Distal leg segments (tarsi and metatarsi, also tibiae) with putative chemoreceptors (Fig. 17), in light microscope similar to sexually dimorphic short vertical hairs but with distal side branches, with regular oblique furrows, and flattened (i.e., with oval diameter); base diameter ~4.5–7.5 µm, length 20–40 µm, diameter proximally 1.7–2.8 µm, at half-length with oval cross section, ~1.5×2.5 µm. Femora, tibiae, metatarsi, and tarsi with round or oval cuticular plates (Fig. 18) at regular intervals, diameter ~4.5–7.5 µm. Base of trichobothria round but with distal bulge and usually with pair of variably distinct lateral humps (Fig. 15); outer diameter of base: 11–18 µm; proximal diameter of seta: 1.3–2.1 µm; retrolateral trichobothrium on tibia 1 at 51–66% of tibia length; prolateral trichobothrium absent on tibia 1. Without slender metatarsal hairs (as described in Huber et al. 2023c, 2024c). Tarsi with 3–4 distinct pseudosegments distally (cf. Fig. 21C), proximally not pseudosegmented. Leg tarsal organs capsulate with small opening (Fig. 19), outer diameter 3.9–7.4 µm, opening diameter 1.0–1.5 µm. Tarsi 4 with two comb hairs distally on prolateral side (Fig. 20D–F). Tarsal claws as usual for family (Figs 20–21); main claws with 7–10 teeth; teeth on tarsus 4 slightly different (shorter and directed more towards distal).
Female
In general, similar to males; often larger; coloration often slightly darker; legs in some species longer than in males (especially in short-legged species; Fig. S4), in other species shorter (especially in long-legged species); without sexually dimorphic short vertical hairs on tibiae. Sternum and clypeus unmodified. Chelicerae without stridulatory files (Fig. 9). Palpal tarsal organ as in males (Fig. 14), usually oval rather than round, opening diameter 1.4–1.9 µm. Other sensory organs and comb hairs on tarsi 4 as in males. Spinnerets as in males (Figs 6–8). Tip of palp with simple pointed process and subterminal invagination (Fig. 14). Epigynum anterior plate trapezoidal to semicircular, with variably distinct pocket or ridge usually in anterior position (e.g., Figs 35, 41), only in I. diroa in central position (Fig. 72) and in I. ziruma sp. nov. in posterior position (Fig. 30). Posterior epigynal plate relatively large but simple, unmodified. Internal genitalia with distinct pore plates on posterior, weakly sclerotized arc (e.g., Figs 29, 36, 41), sometimes with distinct median sclerite (e.g., Figs 100, 104, 108), sometimes with membranous lateral pouches or tubes (e.g., Figs 46, 63, 77, 86), and sometimes with large and complex expandable median sac (e.g., Figs 100, 108, 112, 124, 128; cf. Appendix 3, character 24).
Relationships
The latest molecular phylogeny of Pholcidae (Eberle et al. 2018; Huber et al. 2018) resolved Ibotyporanga as sister to a North and Central American clade including the genera Pholcophora and Papiamenta. This sister group relationship received low support, but it is strongly supported by unpublished UCE data including more representatives of the mentioned genera, and many more representatives of other Ninetinae genera (G. Meng, L. Podsiadlowski, B.A. Huber, unpubl. data).
The monophyly of Ibotyporanga is well supported by several morphological synapomorphies (Fig. 1): median notch on male clypeus (char. 1); reduction of ALS spigots to only two (char. 2); single median apophysis on male chelicerae (char. 3); distinct light band on procursus (char. 10); and median pocket on female epigynal plate (char. 18). In addition, the prolateral sclerite on the bulbous part of the genital bulb (char. 13) might be a further synapomorphy (see Discussion).
Internal relationships appear reasonably well resolved in the morphological cladogram (Fig. 1) but ten of the 15 nodes in this tree are supported by a single character each, and very few groups receive additional support from CO1 sequences (cf. Fig. S2). The cladistic analysis suggests that species with a ‘regular’ procursus (i.e., not slender and elongated; char. 6) are plesiomorphic, while those with a slender elongated procursus are derived and monophyletic. Within this clade, species with a ‘split’ procursus, i.e., with a distinct dorsal branch in addition to the main branch (char. 8), are again resolved as a monophylum.
Natural history
Ibotyporanga spiders are typically found in dry habitats, dominated by low and thorny vegetation (Figs 22–23). Some species were found on bare rock outcrops, under rocks lying in the plain sun, while others were found in low and dry forests. They seem to avoid more humid habitats even when available nearby (see I. kanoe sp. nov.). Several species also occupy highly degraded and artificial habitats, such as roadside rocks, piles of construction materials, and pastures; two species are known to enter buildings, and of these, I. naideae has probably extended its original distribution by human transport.
Within these habitats, any sheltered space at ground level seems to be suitable for Ibotyporanga, but the most common microhabitat was under stones. The spiders were also found under and in other objects lying on the ground such as dead branches and tree trunks, cacti, bromeliads, and bark, and rarely even in the leaf litter or (I. naideae only) in the understory vegetation. Different species do not seem to be specialized to specific microhabitats: several species were found in a variety of different microhabitats.
In some cases, the microhabitat was shared with another species of Pholcidae, usually another representative of Ninetinae. In Brazil, this was usually a representative of Kambiwa; in northern South America, it was Galapa Huber, 2000. Highly degraded and artificial habitats were often shared with synanthropic species such as Modisimus culicinus (Simon, 1893) or Physocyclus globosus (Taczanowski, 1874). In a few cases, we found two species of Ibotyporanga to share a habitat or even a microhabitat. For example, Ibotyporanga emekori was found together with different congeners (I. diroa; I. itajubaquara sp. nov.; I. tuxa sp. nov.), apparently in identical microhabitats; I. naideae was found to share localities with I. guanambi sp. nov., I. imale sp. nov., and I. sertao sp. nov.; I. sertao sp. nov. was also found together with I. xakriaba sp. nov.
Upon disturbance, the spiders usually started to run rapidly until finding a new hiding place, often just a small depression in the rock. In some species, however, a sexual dimorphism in this behavior was observed, with males running but females remaining sitting on the rock or feigning death when beaten out of a branch or cactus.
Egg sacs were usually round but slightly flattened (Figs 25, 55), with a diameter of ~1.5–2.5. They were covered by a very sparse and poorly visible layer of silk. They contained ~10– 40 eggs (in most cases 15–30). Egg diameters ranged from 0.46 to 0.62, with a positive correlation between egg diameter and body size (carapace width) (Fig. S5).
For further details on individual species, see species descriptions below.
Distribution
Ibotyporanga is apparently restricted to South America (Fig. 24). Here, it is largely limited to two areas dominated by dry and semi-arid environments: the northern South American coast, and the Brazilian Cerrado and Caatinga biomes. The genus seems to be absent from the Andes; the highest known record is at 1160 m a.s.l. Ibotyporanga is largely absent from the Amazon biome. The finding of I. kanoe sp. nov. in Rondônia suggests that within the Amazon biome, Ibotyporanga may be limited to small pockets of relatively dry environments (cf. Fig. 22B). In northern South America, Ibotyporanga is remarkably absent from the Leeward Antilles (Huber et al. 2024a).
On lost types
It seems that the type specimens (and most non-type specimens) of all four previously described Brazilian Ibotyporanga species are lost. The type series of I. naideae Mello-Leitão, 1944 was apparently destroyed in the fire that burned a large part of the collection of the Museu Nacional do Rio de Janeiro on 2 Sep. 2018 (A. Kury, personal communication, 22 Nov. 2023). All specimens of the three species described in Huber & Brescovit (2003) (I. diroa, I. emekori, and I. ramosae) were apparently destroyed in the fire that burned a large part of the scorpion and spider collections at Instituto Butantan (São Paulo) on 15 May 2010 (A.D. Brescovit, personal communication, 1 Sep. 2023). We do not designate neotypes for these species as we see no “exceptional need” (ICZN Art. 75) for doing so.
Composition and species limits
The genus now includes 24 nominal species. Of these, a few show geographical morphological variation that may represent species limits, i.e., they need to be restudied with larger samples and more data (e.g., molecular). In some species, we found unusually high genetic distances among putative conspecifics (Figs S5–6, Table S1). Particularly problematic in this sense are the type species (I. naideae) and I. imale sp. nov.; but also I. walekeru sp. nov., I. guanambi sp. nov., I. emekori, I. kiriri sp. nov., and I. canudos sp. nov.; see individual species descriptions below for evidence suggesting that each of these species may eventually need to be split into two or more species.
Three further probable species are available in collections but not formally described, either because no males are available, or because the material is in very poor condition: (1) I. “Ven18-182” from Venezuela (Falcón, Peninsula de Paraguaná, near Cueva del Guano, 11.9026° N, 69.9456° W; ZFMK Ar 21861; Fig. 26) is included in the trees in Figs S2, S 3, and S6. The epigynum and internal genitalia of the only available adult specimen were illustrated in Huber & Villarreal (2020: figs 197–199). (2) I. “Br22- 182” from Brazil (Bahia, E of São Félix do Coribe, top of hill, 13.4040° S, 44.1100° W; CHNUFPI 9066 [deposited in ZFMK Br22-182]; Fig. 74) could not be sequenced (barcoding failed). The epigynum and internal genitalia of the only available adult specimen are similar to those of I. imale sp. nov. (which was found at the base of the same hill), but the legs are much longer (tibia 1: 1.60; in 54 females of I. imale: 0.95–1.33). (3) I. “Geneve453” from Colombia (Magdalena, Tayrona National Park, Bahia de Gairaca, 11.317° N, 74.108° W; MHNG; Fig. 26). The available specimens (3 ♂♂, 3 ♀♀, 1 juv.) are strongly bleached and difficult to study. The shape of the procursus (S-shaped) strongly suggests that it represents an additional species.
description: Published as part of Huber, Bernhard A., Meng, Guanliang, Král, Jiří, Ávila Herrera, Ivalú M. & Carvalho, Leonardo S., 2024, Diamonds in the rough: Ibotyporanga (Araneae, Pholcidae) spiders in semi-arid Neotropical environments, pp. 1-169 in European Journal of Taxonomy 963 on pages 11-29, DOI: 10.5852/ejt.2024.963.2687, http://zenodo.org/record/13963130