Ceratogyrus attonitifer Engelbrecht, 2019

Midgley, John M. & Engelbrecht, Ian, 2019, New collection records for Theraphosidae (Araneae, Mygalomorphae) in Angola, with the description of a remarkable new species of Ceratogyrus, African Invertebrates 60 (1), pp. 1-13 : 1

Ceratogyrus attonitifer Engelbrecht, 2019 sp. n. Figures 2B, C , 3A-C , 4A, B

Type material.

Holotype ♀: NCA 2018/334. Angola, Moxico Province. Locality data redacted. 2016/10/31 to 2016/11/04. J.M. Midgley. Excavated from burrows.

Paratypes: 1 ♀: NCA 2018/335. Label data as for holotype. 2 ♀: NMSA 29340 (Type No: 2335). Label data as for holotype. 2 ♀ ZMB/arach 49121, ZMB/arach 49122. Label data as for holotype.

Diagnosis.

Ceratogyrus attonitifer sp. n. can be diagnosed from its congeners, and all other species of Theraphosidae , by the presence of a large, elongate protuberance which extends out of the fovea and over the spider’s abdomen (Figure 2 ).

Etymology.

The specific epithet is derived from the Latin root attonit-, meaning astonishment or fascination, and the suffix -fer, bearer of or carrier, and refers to the astonishment felt by the authors at the discovery of this remarkable species.

Generic placement.

The presence of distinct scopulae made up of plumose setae on the retrolateral surfaces of the chelicerae support the inclusion of this species in the Harpactirinae . The new species is placed in the genus Ceratogyrus on the basis of the presence of a foveal protuberance. While not all Ceratogyrus species possess a foveal horn or protuberance, all known species of the theraphosid subfamily Harpactirinae which do possess such a structure are placed within this genus. A diagnosis for the genus Ceratogyrus is provided in Gallon (2001).

Description.

Measurements are presented in Table 2 .

Carapace (Figure 3A, B ): Golden brown with paler coloration distally; ovate, hirsute with fringe of longer, pale setae on lateral and posterior margins. Cephalic region flat in lateral profile, not distinct from thoracic region. Ocular tubercle distinct with eye pattern as in Figure 4A . Eye sizes (mm): AME: 0.3 (0.27-0.32), ALE: 0.46 (0.36-0.51), PME: 0.22 (0.18-0.25), PLE: 0.41 (0.38-0.44). ALE larger than all other eyes, ca. 1.5x diameter of AME; PLE larger than PME, AME and PLE similar in size. Clypeus relatively wide, straight, with fringe of short, anteriorly oriented setae on anterior margin. Fovea strongly procurved with prominent, elongate protuberance extending over dorsal aspect of abdomen, as long as or longer than carapace length, anterior part extending from carapace sclerotized, remainder soft and membranous, bag-like in living specimens, becoming shrivelled when preserved, dark in colour.

Chelicerae: Golden brown, hirsute on dorsal, prodorsal and anterior surfaces. Retrolateral surface concave, more so ventrally, with distinct, well developed scopula of plumose setae. Prolateral surface with fine, sparse setae, no plumose setae; ventral surface with single row of seven large teeth along promargin and single, small depression anterior to first tooth; >10 smaller teeth or denticles on proximal ventral surface external to larger teeth. Promargin with long, slender, grey setae; retromargin with long, red, wooly setae corresponding to those on maxilla.

Sternum, labium and maxillae (Figure 3C ): sternum densely hirsute with short black setae, longer setae marginally and anteriorly. Sigilla not apparent. Labium sparsely hirsute with elongate, slender setae and ca. 60-85 cuspules. Maxillae densely covered in 250-320 cuspules on proximal region of ventral surface; ventral surface also with sparse medium to long, slender setae, becoming shorter on retrolateral surface. Prolateral surface with sparse, elongate setae; proventral margin with elongate, red, woolly setae, no spiniform setae present.

Legs and pedipalps: all femora golden brown dorsally; palps and legs I and II dark brown for remainder of dorsal and retrolateral surfaces; legs III and IV golden brown for remainder of dorsal surface. Palps and legs I and II dark brown to black ventrally and prolaterally as is typical for the genera Ceratogyrus and Augacephalus ( Gallon 2005). Legs III and IV with alternating broad, pale and narrow dark brown bands as follows: majority of femora yellow-brown but with proximal and distal margins dark brown, patella dark brown, tibia yellow-brown. Palp and leg tarsi scopulate for entire ventral surface; all leg tarsi with paired claw tufts concealing paired tarsal claws, third claw absent, but a small triangular patch of longer scopular setae is present in its place. Metatarsi scopulate, scopulae entire for legs I-III, divided by longitudinal row of setae on leg IV. Scopulae broad and covering almost entire non-articulating surfaces of metatarsi I and II, approximately distal ¾ of metatarsus III, narrow and tapering for metatarsus IV covering distal 2/3 of non-articulating surface. Dorsal surface of palp and leg tarsi with long, scattered setiform trichobothria and two distal submedian rows of short, clavate trichobothria. For palps and legs I, II, III, and IV counts of clavate trichobothria as follows: 6-21, 12-27, 13-30, 16-29, 15-29. Spination: all leg tibia with 1DPV, 1DRV; metatarsi III and IV with 1DPD, 1DRD; remaining segments without spines.

Abdomen: densely hirsute with short setae and more sparse, elongate setae; dorsal and lateral surfaces brown with golden speckles. Ventrally, book lungs covered with pale, yellow-brown transverse bands, separated by narrow, black band of setae, remainder of ventral surface posterior to book lungs, and spinnerets, black. Distal segment of posterior spinnerets digitiform, but not markedly elongate.

Spermathecae (Figure 4B ): Simple, paired, unlobed, flattened in cross section; relatively broad, widening at their base, no swollen terminus. Not diagnostic within the genus.

Additional material.

NCA2018/328: 1 imm. Angola, Moxico Province. Locality data redacted. 2016/11/20. W. Conradie. Pitfall traps .

Ecology.

Ceratogyrus attonitifer sp. n. occurs in miombo woodland in south-eastern Angola. All specimens were collected from open burrows in sandy soil in dambos, between the high-water flood line and the miombo woodland edge (Figure 2A ). Burrows (Figure 2D ) were approximately 40 cm deep, and near vertical with a horizontal chamber at the bottom. Burrow entrances have a low collar made of silk and incorporate surrounding grass and twigs, but the collar is not as large and distinctive as in some other species of Ceratogyrus . The entrances are often hidden among grass tufts, but may also be found in open sand. Any object inserted into the burrow was attacked enthusiastically.

Indigenous knowledge.

This species is known as “Chandachuly” in the Luchazi language. It was reported that they prey mainly on insects. The venom is not considered to be dangerous, though bites may result in infections which can be fatal due to poor medical access. It is claimed that the females enlarge existing burrows rather than digging their own burrows, though this needs to be verified as both behaviours are known in harpactirines.

Figures

Figure 2. Habitat, burrow and live habitus of Ceratogyrus attonitifer sp. n. in south-eastern Angola. A Aerial view of habitat at the type locality showing a dambo (wetland) amongst miombo (Brachystegia) woodland. The expedition campsite is to the right of the dambo. Specimens were collected primarily along the margins of the wetland area B live habitus, dorsal, showing full size of the foveal protuberance in life C specimen in defensive posture typical for baboon spiders; background is white sand at the type locality D burrow entrance amongst grass tussocks; entrance approximately 2 cm wide.

Figure 3. Ceratogyrus attonitifer sp. n. paratype, cephalothorax. A retrolateral view B dorsal view C ventral view. Scale bar: 10 mm (A).

Figure 4. Ceratogyrus attonitifer sp. n. paratype. A ocular tubercle showing eye pattern B spermathecae. Scale bars: 1 mm (A); 0.5 mm (B).