Macroctenus nimba, Henrard & Jocqué, 2017

Henrard, Arnaud & Jocqué, Rudy, 2017, Morphological and molecular evidence for new genera in the Afrotropical Cteninae (Araneae, Ctenidae) complex, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 180 (1), pp. 82-154 : 107-115

MACROCTENUS NIMBA SP. NOV.

( FIGS 15A – F , 16A – F , 17A – D , 18A – D , 19A – D, 20A – I )

http://zoobank.org/ urn:lsid:zoobank.org:act:CB2853EA-2540-477B-B6B6-9736FEFA6196

Type material

Holotype, female: GUINEA: Mt. Nimba, Chateau ^, 7 ° 40 0 N, 8 ° 23 0 W, 778 m asl, 11.X.11, hand collecting with headlamp inside dry adit, on walls and beams, at 5 – 20 m depth, Van den Spiegel D. & Henrard A. ( DNA-N43 , MRAC 238119 ).

Paratypes: GUINEA, Mt. Nimba : 1 ♂: Geology Base K 1, 7 ° 39 0 N, 8 ° 22 0 W, 1479 m asl, 28.I.2012, humid adit, with bats, Van den Spiegel D., Henrard A., Allard C., Bimou P. & Sidibe M. ( DNA-N01 , MRAC 237842 ) ; 1 ♀: Geology Base K 2, 7 ° 39 0 N, 8 ° 22 0 W, 1479 m asl, 28.I.2012, humid adit, with bats, Van den Spiegel D., Henrard A., Allard C., Bimou P. & Sidibe M. (DNA- N02, MRAC 238211 ) ; 1 ♂: Zougue Cave , 7 ° 40 0 N, 8 ° 23 0 W, 968 m asl, 27.I.2012, with bats, on wall of lower humid cave, Van den Spiegel D., Henrard A., Allard C., Bimou P. & Sidibe M. ( MRAC 238212 ) ; 1 ♂: Zougue Cave , 7 ° 40 0 N, 8 ° 23 0 W, 968 m asl, 27.I.2012, hand collecting, upper cave, near Zougue river, Adrian Hudson ( MRAC 238215 ) ; 1 ♀: Geology Base , 7 ° 39 0 N, 8 ° 22 0 W, 1560 m asl, 9.III.2012, hand collecting, in a natural cavity among rocks in altitude meadows, near adit T4 , Van den Spiegel D., Henrard A., Allard C., Bimou P. & Sidibe M. ( MRAC 238907 ) ; 1 ♂ 1 ♀: Geology Base K3, 7 ° 40 0 N, 8 ° 22 0 W, 1560 m asl, 01.II.2012, hand collecting, on wall of humid cave, Van den Spiegel D., Henrard A. & Allard C. & Bimou P. & Sidibe M. ( MRAC 238912 ) ; 1 ♀: Geology Base K3, 7 ° 40 0 N, 8 ° 22 0 W, 1492 m asl, 09.III.2012, hand collecting, adits K3 (10 – 50 m), Van den Spiegel D., Henrard A. & Allard C. & Bimou P. & Sidibe M. ( MRAC 238915 ) ; 1 ♀ with cocoon: Bassin 3, 7 ° 40 0 1.128 ″ N, 8 ° 22 0 59.112 ″ W, 1489 m asl, 8.III.2012, hand collecting, in rock anfractuosity, near the road, Van den Spiegel D., Henrard A. & Allard C. & Bimou P. & Sidibe M. ( MRAC 238926 ) ; 1 ♀: Base geology K1, 7 ° 40 0 N, 8 ° 22 0 W, 1479 m asl, 09.III.2012, hand collecting, on rock face near the ground, Van den Spiegel D., Henrard A. & Allard C. & Bimou P. & Sidibe M. ( MRAC 238935 ) ; 1 ♀: Pierre Richaud , 5 – 20 m deep inside the adit, on walls, 7 ° 39 0 N, 8 ° 22 0 W, 1502 m asl, 10.X.2011, headlamp collecting, Van den Spiegel D. & Henrard A. ( DNA-N44 , MRAC 238098 ) .

Other material

GUINEA: 1 ♀: Mt. Nimba, Zougue River , campsite SMFG near ‘Charly 1’, on a rock near the river, 7 ° 42 0 N, 8 ° 24 0 W, 770 m asl, 06.II.2012, night collecting, Van den Spiegel D., Henrard A., Allard C., Bimou P. & Sidibe M. ( DNA-N13 , MRAC 238918 ) .

Etymology

The species name is a noun in apposition taken from the type locality.

Diagnosis

Macroctenus nimba sp. nov. specimens differ from those of M. kingsleyi and M. vandenspiegeli sp. nov. by the presence of four pairs of dark spots each with a tiny white patch on the abdomen dorsum ( Figs 16A, B, F , 17A, b ); epigyne ( Figs 18C , 20A, D, G ) with a shorter MS, much smaller spermathecae ( Figs 18D , 20B, C, E, F, H, I ), their diameter apart whereas they are only half their diameter apart in M. kingsleyi ( Fig. S6B, E ). Females of M. occidentalis have black abdominal spots ( Fig. S7A ) but the lateral parts of the MS are protruding forward ( Fig. S7B, C, D, G ). Males are recognized by the less dense ventral pilosity of the palp, the shape of the MA ( Figs 18A , 19C, D) which is elongate and of the RTA ( Fig. 19B) which is short, does not reach the anterior margin of the tibia and is slightly indented at the tip.

Description

Female (holotype). Total length 25.8. Carapace 12.8 long and 9.2 wide. Clypeus 0.46 high. Eye diameters: AME 0.85, ALE 0.49, PME 0.89, PLE 0.59. Coloration (in ethanol): carapace pale brown with pattern of short dark hairs: two slightly sinuous lines behind PLE, radiating striae from fovea, posterior one forming a pale cross with longitudinal pale median band. Chelicerae medium brown; mouthparts pale brown; sternum yellowish brown; legs pale brown with dense dark pilosity on Fe and T. Abdomen dorsum dark grey with faint paler median band in frontal half, followed by four pairs of dark spots; sides dark with numerous longitudinal pale lines; venter dark grey with two oblique pale lines and two rows of pale spots between them. Living specimens ( Fig. 16A – C, E, F ) with much more contrasted coloration pattern. Chelicerae with three promarginal teeth, median larger; four retromarginal teeth, proximal distant from the remaining three, basal smallest; intermarginal denticles present. Leg measurements: I: femur 13.3 patella 5.7/ tibia 13.3/ metatarsus 13.6/ tarsus 4.7/ total 50.8; II: 12.9/ 5.2/ 12.1/ 12.1/ 4.0/ 46.3; III: 11.4/ 5.5/ 9.2/ 10.2/ 3.7/ 40.0; IV: 14.3/ 4.1/ 12.5/ 15.6/ 4.3/ 52.7. Leg formula 4123. Leg spination: femur I pl1-1- 1-1 d1-1-1 rl1-1-1-1, II pl1-1-1-1 d1-1-1 rl1-1-1, III pl1-1-1-1 d1-1-1 rl1-1-1-1, IV pl1-1-1-1 d1-1-1 rl1-1-1- 1; patella I pl1 rl1, II pl1 rl1, III pl1 rl1, IV pl1 rl1; tibia I v2-2-2-2 pl1-1 d1-1-1 rl1-1-1, II v2-2-2-2 pl1-1 d1-1-1 rl1-1-1, III v2-2-2 pl1-1 d1-1-1 rl1-1, IV v2-2-2 pl1-1 d1-1-1 rl1-1; metatarsus I pl1-1-1 rl1-1-1, II pl1-1 rl1-1-1, III v2-2-2 pl1-1-1 d1-1 rl1-1-1, IV v2-2-2 pl1-1-1 d1-1-1 rl1-1-1; Mt IV not modified. Epigyne ( Figs 18C , 20A, D, G ) with broad MS with smoothly rounded lateral margin; LS with short and sharp LP. Vulva ( Figs 18D , 20B, C, E, F, H, I ) with copulatory ducts short; spermathecae small, ovoid, as far as largest diameter apart; fertilization ducts curved, directed posteriorly.

Male (paratype, MRAC 238215). Total length 22.6. Carapace 11.9 long and 8.9 wide. Clypeus 0.59 high. Eye diameters: AME 0.45, ALE 0.39, PME 0.69, PLE 0.59. Coloration (in ethanol): carapace reddish brown with dark pattern behind eyes and on radiating striae; pale stripes less pronounced than in female. Living specimens ( Figs 16D , 17A, B ). Chelicerae dark brown; mouthparts and sternum medium brown; legs medium brown; abdomen dorsum dark brown with four pairs of dark spots; sides and venter grey. Chelicerae with three promarginal teeth, median larger; four retromarginal teeth, proximal distant from the remaining three, basal smallest; intermarginal denticles present. Leg spination: femur I pl1-1-1-1 d1-1-1 rl1-1-1, II pl1-1-1-1 d1-1-1 rl1-1-1, III pl1-1-1-1 d1-1-1 rl1-1-1-1, IV pl1-1-1-1 d1-1-1 rl1- 1-1; patella I, II none, III pl1 rl1, IV pl1 rl1; tibia I v2-2-2-2 pl1-1-1 rl1-1, II v2-2-2-2 pl1-1-1 rl1-1, III v2- 2-2 pl1-1 d1-1-1 rl1-1, IV v2-2-2 pl1-1 d1-1-1 rl1-1; metatarsus I v2-2-1 pl1 rl1, II v2-2-1 rl1, III v2-2-2 pl1-1-1 d1-1 rl1-1-1, IV v2-2-2-1 pl1-1-1 d1-1 rl1-1-1; Mt IV unmodified. Palp ( Figs 18A, B , 19A – D, 21A, B): tibia densely hairy, with three long spines, ventral and retrolateral process on distal margin; RTA short, not reaching distal margin of tibia, tip not sharp but slightly indented and with tiny projection in ventrolateral view; cymbium with shallow prolateral concavity delimited by dorsal and ventral basal swellings; MA fairly long, with almost parallel margins, slightly curved, distally with slight prolateral indentation; embolus flat, curved; conductor membranous, c-shaped.

Natural history

Macroctenus nimba was first discovered in handmade adits located above 1000 m asl ( Fig. 15D – F ). Then it was also found in natural caves or small rock cavities, always at high altitude ( Fig. 15A – C ). Two females were observed suspended from their cocoon which was fixed to the roof of an adit ( Fig. 16C is actually inverted). When disturbed, the female vigorously protected the cocoon by grabbing it between the fangs. One cocoon was transferred to the lab where it hatched. The juveniles went through a dozen moults before maturity. They were fed with small flies during the early stages, then with crickets or cockroaches. During prey capture, the spider turned toward the cricket standing on six legs with the first pair raised straight above the substrate. When the prey was close enough, the spider darted at it, using the first legs to draw the prey towards the chelicerae. In cases where the immobilized prey was as large as the ctenid or larger, it was fixed on a vertical surface with silk ( Figs 16E, F ) before it was eaten, the spider facing down. This behaviour was also observed in mine adits where the prey was fixed to the rock wall ( Fig. 16E ) and with other ctenids in the forest where the prey was fixed with silk on a large suspended leaf. A very similar behaviour was also observed for Phoneutria boliviensis (F. O. Pickard-Cambridge, 1897) by Hazzi (2014). One to two days after the last moult of the males, two small sheet-webs were invariably found in their cages ( Fig. 17C, D ). These sheet-webs are assumed to be sperm-webs, apparently one for each palp. Unfortunately, all attempted matings were unsuccessful.

Distribution

Only know from Mt. Nimba in Guinea.

Figures

Figure 6. Evolution of the characters mapped on the majority rule consensus tree based on morphological data (Fig. 5). Black circles indicate non-homoplasious changes, and white circles homoplasious changes. Character numbers are placed over the circles, and the states are shown below the circles. A, Non-Cteninae; B, Cteninae, part 1; C, Cteninae, part 2.

Figure 7. Amicactenus mysticus sp. nov.: A, B, Ht male (DNA-N06, MRAC 238226); C, D, Pt female (MRAC 238919); A, male carapace, dorsal view; B, male abdomen, dorsal view; C, female carapace, dorsal view; D, female abdomen, dorsal view. Scale bars = 2 mm.

Figure 15. Field photos where specimens of Macroctenus nimba sp. nov. were found: A, landscape of alpine meadows on crests of Mt. Nimba; B, surveys near the adits ‘T4’ at ‘Bassin 3’, Sempere; C, Henrard Arnaud exploring some natural cavities among rocks at ‘Geology Base’ in altitude meadows; D, Van den Spiegel Didier and Henrard Arnaud collecting inside the the adits ‘T4’ at ‘Bassin 3’, Sempere; E, Bimou Prosper and Sydibe Mamadou at the entrance of the adit ‘K1’ at ‘Geology Base’; F, as previous, inside the adit.

Figure 16. Macroctenus nimba sp. nov.: A, Ht female (DNA-N43, MRAC 238119) found in a dry adit at ‘Ch^ateau’; B, Pt female (DNA-N02, MRAC 238211) found at ‘Geology Base’, adit ‘K2’; C, female defending her cocoon in the adit ‘T4’ at ‘Bassin 3’, Sempere; D, Pt male (DNA-N01, MRAC 237842) in the adit ‘K1’ at ‘Geology Base’; E, female feeding on prey fixed to the wall photographed in the adit ‘K2’; F, female in captivity, having caught a roach. Note the prey fixed on the glassy wall.

Figure 17. Macroctenus nimba sp. nov.: A. male in captivity; B, as previous, detail; C, sperm web (arrows); D, as previous, detail.

Figure 18. Macroctenus nimba sp. nov.: A, B, Pt male (MRAC 238215); C, D, Pt female (DNA-N44, MRAC 238098); A, male palp, retrolateral view; B, as previous, ventral view; C, epigyne, ventral view; D, as previous, dorsal view. Arrow indicates plug. Scale bars = 1 mm.

Figure 20. Macroctenus nimba sp. nov., female genitalia: A–C, Ht female (DNA-N43, MRAC 238119); D–F, Pt female (DNA-N02, MRAC 238211); G–I, Pt female (DNA-N44, MRAC 238098); A, epigyne, ventral view; B, as previous, dorsal view; C, as previous, dorsolateral view; D, epigyne, ventral view; E, as previous, dorsal view; F, as previous, dorsolateral view; G, epigyne, ventral view; H, as previous, dorsal view; I, as previous, dorsolateral view. Scale bar = 1 mm.