Metagonia uca Huber, 2025

Metagonia uca Huber sp. nov.

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Figs 1E – F, 2E – F, 13 – 16

Diagnosis

Easily distinguished from most known congeners (except M. mariguitarensis and M. wayuu sp. nov.) by strongly asymmetric male palps ( Fig. 13), by male chelicerae with pair of strong lateral protrusions ( Fig. 15D), and by female external and internal genitalia ( Figs 15F, 16; epigynum with posterior semicircular process, or ‘scape’; internal genitalia with complex system of pouches, ducts, and folds). Distinguished from both M. mariguitarensis and M. wayuu by different color pattern on carapace (both in males and females; Fig. 2), by larger size and longer legs (e.g., male tibia 1>6.5 vs <5.0; female tibia 1>5.5 vs <4.0), and by female genitalia (epigynal scape with asymmetric groove; Fig. 16B). Further distinguished from M. mariguitarensis by male chelicerae with pointed rather than rounded distal apophyses ( Fig. 15D), by main branch of left procursus without distinctive ventral indentation (compare Fig. 4C with Fig. 14C), by absence of hair-like process on right procursus (compare Fig. 4D with Fig. 14D), and by stronger palpal asymmetry, i.e., absolutely and relatively bigger right palp (e.g., right/left tibia diameter> 2.6 vs<2.5; see also Fig. 22).

Etymology

The species name alludes to fiddler crabs ( Uca and other genera), where the males have a major claw significantly larger than the minor claw.

Type material

Holotype

COLOMBIA – Quindío • ♂; Armenia, Universidad del Quindío ; 4.5537° N, 75.6608° W; 1500 m a.s.l.; 8 Sep. 2022; B.A. Huber and G.A. Rodríguez leg.; MUSENUV Ar 3533 .

GoogleMaps

Paratypes

COLOMBIA – Quindío • 1 ♂, 2 ♀♀; same collection data as for holotype; MUSENUV Ar 3534 • 7 ♂♂, 9 ♀♀; same collection data as for holotype; ZFMK Ar 24781 , 24782 GoogleMaps .

GoogleMaps

Other material examined

COLOMBIA – Quindío • 3 ♀♀, 1 juv., in pure ethanol; same collection data as for holotype; ZFMK Col238 (voucher of UH542 ) GoogleMaps • 1 ♀; 3 km N of Circasia, Reserva Bosque del Silencio ; 4.6411° N, 75.6379° W; 1850 m a.s.l.; 7 Sep. 2022; B.A. Huber and G.A. Rodríguez leg.; ZFMK Ar 24783 GoogleMaps • 2 ♀♀, in pure ethanol; same collection data as for preceding; ZFMK Col237 (voucher of UH254 ) GoogleMaps . – Risaralda • 1 ♀; La Celia, Vereda San Eugenio ; 4.970° N, 75.006° W; 1600 m a.s.l.; 25 Feb. 2010; N. Betancour leg.; MUSENUV 2214 GoogleMaps • 1 ♀; same collection data as for preceding; MUSENUV 2220 GoogleMaps • 1 ♂, 1 ♀; same collection data as for preceding; MUSENUV 2226 GoogleMaps .

Description

Male ( holotype)

MEASUREMENTS. Total body length 3.2, carapace width 0.9. Distance PME–PME 250 µm; diameter PME 120×130 µm; distance PME–ALE 30 µm; AME absent. Leg 1: 31.5 (7.8 +0.5+7.7+14.0 +1.5), tibia 2: 4.9, tibia 3: 2.8, tibia 4: 4.4; tibia 1 L/d: 86; diameters of leg femora (at half length) 0.10 – 0.11; of leg tibiae 0.09.

COLOR (in ethanol). Carapace anteriorly pale ochre-yellow, posterior half dark brown ( Fig. 2E), ocular area with brown pattern, clypeus brown; sternum whitish; legs ochre-yellow, patellae and tibia-metatarsus joints dark brown; abdomen pale ochre-gray, dorsally and laterally with dark and whitish marks.

BODY. Habitus as in Fig. 1E. Ocular area slightly raised. Carapace without thoracic groove. Clypeus with strongly sclerotized rim ( Fig. 15A). Sternum wider than long (0.68/0.56), unmodified. Abdomen approximately twice as long as wide, dorso-posteriorly pointed.

CHELICERAE. As in Fig. 15D – E; with pair of lateral conical processes, pair of distal frontal processes set with ~12 – 14 modified (globular) hairs each, and pair of diverging apophyses near fang joints.

PALPS. As in Fig. 13; coxa unmodified, apparently symmetric; all other segments directionally asymmetric, see below; trochanter with short ventral apophysis; femur with distinct process on prolateral-ventral side; procursus consisting of main branch and ventral hinged process; genital bulb simple, consisting of globular part and embolus.

ASYMMETRY. Right trochanter slightly larger than left trochanter. Right femur rather cylindrical, with cylindrical prolateral-ventral process; left femur smaller, distally strongly widened, and with conical prolateral-ventral process. Right tibia much bigger than left tibia (maximum diameter in lateral view: 0.70 – 0.77 vs 0.25 – 0.27). Right procursus consisting of strongly sclerotized main branch (distally the sclerite is mostly internal, covered by weakly sclerotized and semitransparent cuticle) and weakly sclerotized semitransparent ventral hinged process; left procursus much smaller, with slender main branch, with distally widened and heavily sclerotized ventral hinged process. Right genital bulb with small globular part (diameter 0.30 – 0.34) and long slender embolus; left genital bulb with larger globular part (diameter 0.42 – 0.46) and with shorter and strongly widened embolus ( Fig. 15B – C).

LEGS. Without spines, without curved hairs, without sexually dimorphic short vertical hairs; retrolateral trichobothrium of tibia 1 at 8%; prolateral trichobothrium absent on tibia 1; tarsus 1 with ~25 pseudosegments, very indistinct.

Variation

Males

Tibia 1 in ten males: 6.7 – 7.8 (mean 7.4).

Females

In general very similar to male ( Fig. 1F) but carapace posteriorly with two Y-marks ( Fig. 2F), ocular area and clypeus not darkened, clypeus unmodified, sternum darker (either dark brown with small light spots or light brown and medially ochre). Tibia 1 in 18 females: 5.7 – 6.6 (mean 6.2). Epigynum ( Fig. 16A – C) simple, mostly weakly sclerotized, posteriorly with sclerotized and slightly asymmetric scape (groove on left side; all females same-sided); internal asymmetric structures visible through cuticle; posterior epigynal plate short and indistinct. Internal genitalia ( Figs 15F, 16D – E) with sclerotized receptacle on right side, with complex system of pouches, ducts, and folds (apparently similar to M. mariguitarensis ; cf. Huber 2004: figs 1 – 2); with pair of elongated pore plates (possibly slightly asymmetric, but this might be an artifact of preparation). One cleared female from Vereda San Eugenio apparently identical to female from type locality.

Barcodes

We sequenced two specimens from two localities (geographic distance: 10 km) ( Table 1 View Table 1 ; Fig. 23). The CO1 distance was 0.2% ( Table 2 View Table 2 ). Distances to the other three species treated herein ranged from 18.8 to 20.9%.

Distribution

Known from three neighboring localities in Colombia ( Fig. 24).

Natural history

In Armenia, most specimens were collected from palm leaves in the entrance area of the small secondary forest within the university campus; deeper in the forest they seemed to be very rare or absent. They shared the locality with a second (undescribed, symmetric) species of leaf-dwelling Metagonia . In Reserva Bosque del Silencio, the three females were collected on a single small palm tree; no further specimens were found despite focused search.