Chibchea santosi Huber & Carvalho

Huber, Bernhard A. & Carvalho, Leonardo S., 2019, Filling the gaps: descriptions of unnamed species included in the latest molecular phylogeny of Pholcidae (Araneae), Zootaxa 4546 (1), pp. 1-96: 45-49

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Chibchea santosi Huber & Carvalho

sp. n.

Chibchea santosi Huber & Carvalho  sp. n.

Figs 150–151View FIGURES 148–153, 157, 159, 162View FIGURES 156–163, 164, 167View FIGURES 164–168, 173–174View FIGURES 169–176, 191View FIGURES 189–197

Gen.n. Br16-178: Eberle et al. 2018 (molecular data); Huber et al. 2018: fig. 3.

Type material. BRAZIL: ♂ holotype, UFMG (22734)  ; 3♀ paratypes, UFMG (22617, 22619, 22735); 4♀ paratypes, CHNUFPI (2538); and 3♂ 8♀ 1 juv. paratypes, ZFMK (Ar 20628), Acre, Cruzeiro do Sul, forest near Cruzeiro do Sul International Airport (7.596°S, 72.767°W), 200 m a.s.l., 30.x.2016 (B.A. Huber, L.S. Carvalho, E.O. Machado)GoogleMaps  .

Other material examined. BRAZIL: 1♀, UFMG (22613); and  1♀, ZFMK (Br 16-312), both in pure ethanol, same data as types  . 6♀ 1 juv. in 80% EtOH, ZFMK (Ar 20629); and 1♂ 1♀, CHNUFPI (2500, 2523); 2♀, UFMG 921826, 22053); and 2♀ 1 juv., ZFMK (Br16-315) in pure ethanol, Amazonas, Guajará, forest at Fazenda Colorado, ‘site 1’ (7.525°S, 72.650°W), 225 m a.s.l., 31.x.2016 (B.A. Huber, L.S. Carvalho, E.O. Machado).

Etymology. The species is named for the Brazilian arachnologist Adalberto José dos Santos, coordinator of the Atlantic Forest Pholcidae  project during which this species was collected.

Diagnosis. Distinguished from most similar known congeners ( C. hamadae  , C. valle  , C. amapa  ) by shapes of procursus and bulbal apophysis ( Figs 159, 162View FIGURES 156–163; bulbal process with distinctive ventral sclerite proximally and large dorsal membranous process; procursus tip not bifid, narrower than in C. hamadae  ), by shape of process proximally on male palpal femur ( Fig. 164View FIGURES 164–168), and by external and internal female genitalia ( Figs 167View FIGURES 164–168, 173–174View FIGURES 169–176; epigynal plate semicircular, without posterior processes; narrow elongated pore plates converging anteriorly).

Description. Male (holotype). MEASUREMENTS. Total length 1.55, carapace width 0.70. Distance PME-PME 50 µm; diameter PME 80 µm; distance PME-ALE 40 µm; distance AME-AME 10 µm, diameter AME 20 µm. Leg 1: 10.3 (2.3 + 0.3 + 2.5 + 4.3 + 0.9), tibia 2: 1.7, tibia 3: 1.3, tibia 4: 1.7; tibia 1 L/d: 45.

COLOR (in ethanol). Carapace pale ochre-yellow with indistinct pattern of brown median mark including ocular area and brown lateral marginal bands; clypeus with pair of brown marks below eye triads; sternum brown; legs light brown, tips of tibiae whitish; abdomen pale greenish to blueish gray with blueish marks dorsally and laterally, ventrally with light brown mark in gonopore area and blueish band between gonopore and spinnerets.

BODY. Habitus as in close congeners (cf. Figs 148, 152View FIGURES 148–153). Ocular area slightly elevated. Thoracic furrow present. Clypeus unmodified. Sternum wider than long (0.50/0.34), unmodified.

CHELICERAE. Very similar to C. amapa  (cf. Fig. 156View FIGURES 156–163), pair of processes on fangs mostly on posterior side ( Fig. 157View FIGURES 156–163; barely visible in frontal view).

PALPS. Very similar to C. amapa  (cf. Figs 154–155View FIGURES 154–155) but femur proximal process of different shape ( Fig. 164View FIGURES 164–168); procursus with simple, narrow tip, not bifid ( Fig. 159View FIGURES 156–163); bulbal process with distinctive ventral sclerite proximally, without serrated ventral sclerite distally ( Fig. 162View FIGURES 156–163).

LEGS. Without spines and curved hairs, few vertical hairs; retrolateral trichobothrium of tibia 1 at 12%; tibia 1 without prolateral trichobothrium (present on other tibiae); tarsus 1 with ~20 indistinct pseudosegments.

Male (variation). Tibia 1 in 4 other males: 2.5, 2.5, 2.6, 2.7.

Female. In general similar to male but cheliceral fangs unmodified. Tibia 1 in 23 females: 1.8–2.3 (mean 2.1). Epigynum anterior plate large, semicircular ( Fig. 173View FIGURES 169–176), internal V-shaped arc visible through cuticle; apparently without pockets; posterior plate short and simple, weakly sclerotized. Internal genitalia with pair of elongated pore plates converging anteriorly ( Figs 167View FIGURES 164–168, 174View FIGURES 169–176). ALS with only two spigots each, one strongly widened, one pointed ( Fig. 191View FIGURES 189–197).

Distribution. Known from two neighboring localities in the states of Acre and Amazonas, Brazil ( Fig. 346View FIGURE 346).

Natural history. At the type locality, this species was found in a humid forest, in small holes in the ground under the leaf litter. It built tiny webs and ran away quickly when disturbed. At the forest at Fazenda Colorado, this was the only pholcid species found in a very dry patch of secondary forest close to a pasture; in a neighboring more natural and more humid patch of forest, eight species of Pholcidae  were collected but not this species.