Icaleptes dimorphicus Pereira & Porto & Moya-Guerra & Martínez-Hernández & Pérez-González 2025, sp. nov.
Creators: name: Pereira, Maria Paula
name: Porto, Willians
name: Moya-Guerra, Natalia Andrea De
name: Martínez-Hernández, Neis José
name: Pérez-González, Abel
Publisher: name: Zenodo
Year: 2025
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Opiliones
Icaleptidae
Icaleptes
Icaleptes dimorphicus

description: Icaleptes dimorphicus sp. nov.
urn:lsid:zoobank.org:act: 2FAA4F47-C4CA-4546-8BBB-791CD9F5E4EB
(Figs 1–9, 18)
Type data. Holotype: 1 male (ICN-Ar, MPP00399) from Hierbabuena, Sierra Nevada de Santa Marta, 2 040 masl (10.89513889 N, - 73.99553 W), Magdalena, Colombia, iii.2018, N. Maya coll .. Paratypes: 1 male and 1 female (UA, MPP00717), same data as the holotype. 1 male and 2 females (MACN-Ar 46877, MPP00715), same data as the holotype. 1 male (MACN-Ar 46856, MPP00716), same data as the holotype. 1 male (MACN-Ar 46845, MPP00687) from Cerro Ratón, San Pedro de la Sierra, Sierra Nevada de Santa Marta 1 818 masl (10.89379996 N, - 74.02982804 W), Ciénaga, Magdalena, Colombia, 11.vi.2024, L.A. Martínez, M.P. Pereira, W.L. Porto, L. Benavides, C. Casas. W. Galvis, C.V. Mamani, D. Proud, D. Padierna cols. 1 male and 1 female (MACN-Ar 46835, MPP00688) from around Don Pablo’s farm, San Pedro de la Sierra, Sierra Nevada de Santa Marta 1 177 masl (10.8925 N, - 73.99083 W), Ciénaga, Magdalena, Colombia, 12.vi.2024, L.A. Martínez, M.P. Pereira, W.L. Porto, L. Benavides, C. Casas. W. Galvis, C.V. Mamani, D. Proud cols. 1 male (MACN-Ar 46799, MPP00689), same data as previous.
Etymology. The species name dimorphicus is a Neolatin adjective from the Greek δι- (from δῐ́ς, Lat. dís, Engl. twice, doubly) + μορφή (Lat. morphé, Engl. form, shape) (occurring or existing in two different forms), referring to the remarkable sexual dimorphism in the coxa IV of males.
Diagnosis. Icaleptes dimorphicus sp. nov. differs from Icaleptes malkini by the absence of an immense flat ocularium in males; by the presence of sexually dimorphic coxa IV in males with a protuberance on the retrolateral margin (Fig. 3) and by the male genitalia with a well-defined, narrower and short rutrum and a wide and massive pergula; by the positioning of the spatulate macrosetae in a single horizontal row and by the apex of the lobes of the stragulum not being recurved (Figs. 7–8). Icaleptes dimorphicus sp. nov. is morphologically similar to Icaleptes armasi sp. nov., but can be differentiated by the stout and triangular protuberance on the retrolateral margin of coxa IV in males (Fig. 3C), with a large portion of the medial basal surface tightly joined, and adorned with a small rounded mound (Fig. 3E) versus a long and conical protuberance without the rounded mound, slightly curved anteriorly (Fig. 11C), with the entire medial surface tightly joined in I. armasi sp. nov. (Fig. 11E); metatarsus III of males with swollen calcaneus that occupies the distal 1/4 of the total metatarsus length (Fig. 6E) versus a calcaneus III that occupies the distal half of the total metatarsus length in I. armasi sp. nov. (Fig. 13E); hypertelic chelicerae of males that lack a median projection/denticle on the fixed finger (Fig. 5) versus non-hypertelic male chelicerae that possess a median projection/denticle on the fixed finger in I. armasi sp. nov. (Fig. 12B), and ocularium less dorsally projected (angle between ocularium and post-ocularium region approximately 165°, Fig. 3B) whereas in I. armasi sp. nov. the ocularium is more projected dorsally (angle between ocularium and the postocularium region approximately 150°, Fig. 11B). Moreover, the male genitalia of Icaleptes dimorphicus sp. nov. have two pairs of small spiniform setae located within the calyx of the pergula (Fig. 7B,D) and a rutrum with a rounded apex (Fig. 8B–C) whereas I. armasi sp. nov. has only one pair of small spiniform setae located inside the calyx, with the other pair positioned outside the margin of the calyx (Fig. 14B,D) and a rutrum with a blunt apex (Fig. 15A–B).
Description. Male holotype (ICN-Ar, MPP00399). Dorsum (Figs. 1, 2A, 3A): Scutum magnum bell-shaped, with the dorsal scutum markedly wider than carapace, smooth, entirely unarmed, without any sulci. Anterior margin of carapace straight and with two small granules on each anterolateral margin. Ocularium with broad base, ill-defined, subconical, with rounded apex. Ocularium barely projected dorsally with the angle between ocularium and post-ocularium region approximately 165° (Fig. 3B). Mesotergal scutum with no visible sulci and therefore no clearly defined areas (i.e., mesotergal areas fused). Lateral margins with a row of very small, low granules each (Fig. 3A). Free tergites smooth and unarmed. Coxa IV is barely visible in dorsal view. Venter: Anal operculum unarmed. Coxa IV with prolateral surface somewhat rounded, almost as wide as long (Fig. 2B). Coxa IV with a huge sexually dimorphic protuberance involving most of the retrolateral proximal margin of the coxa and spiracular sternite surface (Fig. 3D). This protuberance is stout and triangular (Fig. 3C), with a big portion of the medial basal surface tightly joined, and adorned with a small rounded mound (Fig. 3E). This sexually dimorphic structure surrounds the genital operculum forming an opercular “tunnel” (Fig. 3C). Spiracles not concealed. Chelicerae (Figs. 4A–B, 5): Stout and unarmed with a bulla not well marked, wide and low (Fig. 4A–B). Chelicerae with sexual dimorphism, males have much larger chelicerae than females (Fig. 5A–B). Movable fingers strongly arched medially forming a proximal opening (like a “hole”) in the fitting region between the cheliceral fingers (Fig. 5C). Cheliceral teeth concentrated only in the distal region of the mobile finger. Pedipalps (Fig. 4C–D): Raptorial morphotype (sensu Wolff et al. 2016) with the dorsal surface of the podomeres smooth and with armature very reduced. Coxa short, unarmed. Trochanter globular, with two small setiferous granules. Femur with two robust ventrobasal spines with wide, low and rounded pedestal. Patella short, armed with a distal mesal setae. Tibia ventrally flattened, slightly convex, and armed with three mesal and two ectal setae (which appear to be reduced spines without pedestals). Tarsus armed ventrally with three ectal and two mesal setae, lacking or with very reduced pedestals. Legs (Fig. 6): Leg measurements in Table 1. Femur I with a row of robust ventral low conical setiferous tubercles. Leg III more robust than leg IV. Metatarsus III thickened distally with calcaneus occupying ¼ of the total length and presenting a central row of modified striate sensilla with pores at the base (with possible glandular function) (Fig. 6E–G). Basitarsus III with the two proximal tarsomeres fused and slightly enlarged (Fig. 6E). Tarsal formula: 3(2):6(3):5:6. Genitalia (Figs. 7–8): Penis tubular with the pars distalis slightly wider than the pars basalis without any other clear distinction between them (Fig. 8A). The ventral region of the pars distalis more apically expanded than the dorsal one forming a stout ventral plate (Figs. 7C, 8E). The apical portion of the ventral plate is differentiated into two tagmata, presumably homologous with the basal pergula and an apical rutrum (Fig. 8E). The pergula is moderately projected and very wide with the ventral apical portion depressed (slightly concave) in form of the shallow calyx (Figs. 7B, D, 8F). The ventral lateral wide region of the pergula contain a horizontal row of six strong spatulate macrosetae and the calyx contain two pairs of small spiniform setae (Fig. 8C). Pars distalis with a dorsoapically short and stout rutrum with a rounded apex and bearing ventrally a pair of small spiniform setae (Figs. 7B, 8E). Capsula externa articulated to truncus as a jackknife (Fig. 8F), formed by a robust stragulum, with well-developed lateral branches widely separated from each other from the middle to the apex, leaving the capsula interna visible in a resting position (i.e., not everted) (Fig. 8B). Capsula interna formed by a wide and cylindrical stylus apically ended in a huge parastylar collar with two pointed lobes (like horns). Color in alcohol: Dark yellow background with darker reticular spots. Live habitus: As shown in Fig. 1.
Female paratype (MACN-Ar 46877, MPP00715) (Fig. 2C–D). Female similar to the male, but with visible and well-marked sulcus I. Ocularium is slightly higher and more pointed than in males (Fig. 2D). Legs III without the enlarged metatarsus and basitarsus. Chelicerae mobile finger without marked curvature medially, with cheliceral teeth appearing from the median region to the apex of the finger (Fig. 5B, D). Coxa IV without the huge triangular sexually dimorphic protuberance. Tarsal formula: 3(2):6(3):5:6.
Variability. Males of Icaleptes dimorphicus sp. nov. exhibits a highly variable external morphology (Fig. 9). We observed that smaller males may present the ventral protuberance of coxa IV reduced to two small projections with rounded apices that barely touch (or do not touch) each other, unlike the large protuberance observed in larger males (described in detail above). These two different degrees of development in the modification of the coxa IV of males may be a sign of a major and minor intrasexual dimorphic condition as defined in Buzatto & Machado (2014), but due to the low number of specimens, we refrain from using minor and major distinctions until further evidence supports the inference and morphological distribution of this putative male polymorphism.
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Distribution. COLOMBIA, Sierra Nevada de Santa Marta, Magdalena, Municipality of Ciénaga, San Pedro de la Sierra (Fig. 18).
description: Published as part of Pereira, Maria Paula, Porto, Willians, Moya-Guerra, Natalia Andrea De, Martínez-Hernández, Neis José & Pérez-González, Abel, 2025, Two new species of Icaleptes (Opiliones: Laniatores: Icaleptidae) from Sierra Nevada de Santa Marta, Colombia, pp. 166-192 in Zootaxa 5563 (1) on pages 168-180, DOI: 10.11646/zootaxa.5563.1.12, http://zenodo.org/record/14595784