Paccius mahimborondro Pett, 2025

Pett, Brogan L., Escobar-Toledo, Jaime & Ferreira, Elodie, 2025, On the genus Paccius (Araneae, Trachelidae) in Madagascar: two new species, redescriptions, and a key to the species, Zootaxa 5716 (2), pp. 257-267 : 262-263

Paccius mahimborondro Pett sp. nov.

Fig. 4

Type material. Holotype ♂: MADAGASCAR: Sofia Province : Mahimborondro protected area ( Réserve de Resources Naturelles de Mahimborondro), 14.300°S, 48.752°E, 1500 m a.s.l., 29.I.2019 – 13.II.2019, Tropical rainforest, leg. M. Jocque et al. (RMCA 247823; BINCO_MAD_19_0080).

Diagnosis. Only P. mucronatus and P.scharffi share with P. mahimborondro sp. nov. a long retrolateral expansion of the cymbium (more than half the length of the cymbium). Paccius mahimborondro sp. nov. is clearly separated from those species by 1) the retrolateral expansion being subtruncate ( Fig. 4D, F ) (vs. smoothly rounded across its length in P. mucronatus ( Fig. 6C, E ) and sharply squared in P. scharffi ( Platnick 2000: fig. 5.9)), and 2) by the RTA being broad (just under half the width of the tibia in retrolateral view) and short (just under half the tibia length) and tapering to a blunt apex ( Fig. 4E, G ); in contrast, the RTA of P. mucronatus is narrow, around 1/5 the tibia width, and short, around 1/4 length of tibia, with a sharp apex ( Fig. 6D, F ), and in P. scharffi the RTA is narrow, around 1/5 the tibia width, and long, around 0.6x as long as the tibia, with a sharp apex ( Platnick 2000: fig. 5.10). Additionally, the field of modified setae extends dorsally to around the midpoint of the cymbium, whereas in P. mucronatus these setae are short and barely project anteriorly from the tibia, and in P. scharffi they are very long and nearly reach the cymbium’s dorsomedian margin. Female unknown.

Etymology. The specific epithet refers to the type locality, Mahimborondro Protected Area; noun in apposition.

Description. Male ( Holotype) ( Fig. 4 ). Measurements. TL 6.88, CL 3.20, CW 2.28, CH 1.22, SL 1.80, SW 1.12, AL 3.68, AW 1.99, chelicera length 1.72, chelicera width 0.84. Legs: I: 2.96, 29, 68, 58, 30. II: 2.20, 1.08, 2.08, 1.64, 1.00. III: 1.60, 0.84, 1.32, 1.40, 0.64. IV: 2.44, 0.96, 2.28, 2.44, 0.88. Eyes: AME 0.18, ALE 0.20, PME 0.14, PLE 0.17.

Colouration: Carapace, chelicerae, labium and maxillae deep red, carapace darker anteriorly, sternum brownish-orange, coxae I and leg I brownish-orange, all coxae and other segments of legs II–IV pale cream. Dorsal sclerite of abdomen orange, with two pairs of sigilla, posterior pair very dark and distinct. Epigastric sclerite purplish-orange, venter generally cream, ventral sclerite light orange with dark spots along length.

Carapace: Broadly subrectangular, surface covered with procurved row of fine setae, relatively high anteriorly with moderate slope toward pedicel, about 2.5x higher at PER than base of pedicel, widest at midpoint of coxae II.

Eyes: PER straight, AER slightly procurved in dorsal view, clearly procurved in frontal view, AME much larger than other eyes, about 2x PME, both lateral eyes protruding on very small tubercles.

Sternum: Shield-shaped, with margins rebordered, triangular extensions between coxae, widest just posterior to coxae I, anterior margin truncated and straight, generally smooth.

Legs: Leg I much thicker and longer than II–IV, devoid of spines, Mt I & II with scopulae and two rows of short black cuspules.

Chelicerae: Robust, tubercles dorsal to fang running along promarginal line, five subequal teeth on promargin, middle one largest, distal two much smaller (most distal tooth borders denticle), four equally sized teeth on retromargin.

Abdomen: Oval, about 3x longer than wide, covered nearly entirely by dorsal sclerite (lacking at anterolateral margins), widest and highest at anterior margin, ventral sclerite long and subrectangular, covering most of venter.

Pedipalp ( Fig. 4D–G ): Anterior margin of tibia wide, about same as length; four or five median boat-shaped seta wrapped together in long sharp claw-shaped structure around 1.1x the thickness of tibia; RTA broad basally, tapering to blunt apex (just under half tibia width in retrolateral view) and short (just under half tibia length); cymbium number “6” shaped, with long retrolateral expansion of cymbium, over half cymbium length, subtruncate margin with only small sinuousities, thus truncated portion is very long and around half cymbium length; tegulum roughly oval, with nearly straight retrolateral margin, sperm duct running along perimeter of tegulum, with three distinct vein-like structures running transversely across tegulum; embolus arising posterolaterally at margin of tegulum, ca. 05:30 position, running clockwise for entire half around rim of tegulum, with very slim thread-like apex at ca. 1 o’clock position.

Distribution. Only known from the type locality.

Figures

FIGURE 4. Paccius mahimborondro sp. nov., holotype male (RMCA 247823). A Habitus, dorsal; B Idem, lateral; C Idem, ventral; D, F Left palp, ventral; E, G Idem, retrolateral. Scale lines: A = 2 mm; D = 0.5 mm.

FIGURE 6. Paccius mucronatus Simon, 1898, holotype male (AR14402). A Habitus, dorsal; B Idem, ventral; C,E Left palp, ventral; D, F Idem, retrolateral. Scale lines: A = 2 mm; no scale bars provided for palp photos.