Ikuma larseni, Zonstein & Marusik, 2022

Zonstein, Sergei & Marusik, Yuri M., 2022, Redescription of the poorly known genus Ikuma Lawrence, with synonymy and description of a new species from Namibia (Araneae, Palpimanidae), African Invertebrates 63 (2), pp. 105-119 : 105

Ikuma larseni sp. nov.

Figs 2 , 3 , 4 , 5 , 6 , 7 , 8

Etymology.

The specific name is a patronym after Norman Larsen (Cape Town, South Africa) who kindly provided us with the macro-photographs of the preceding Ikuma species.

Types.

Holotype ♀, Namibia, Erongo Region, Namib-Naukluft National Park, Gobabeb, 23°34'S, 15°03'E, 8-9.ii.1969, B. Lamoral (NMSA-SPI-26895). Paratypes: 1♀, same collection data but 14.iv.1969, E. Holm (NMSA-SPI-26881); 1♀, same collection data but 14.iii.1970, no collector’s name indicated (NMSA-SPI-11682); 1♀, same collection data but 1-29.ii.1972, B. Lamoral (NMSA-SPI-11210); 1♂, same collection data but Narras Valley 10 km W Gobabeb, 570 m (1700 feet), 2.x.1984, C. Griswold (NMSA-SPI-26894).

Diagnosis.

Ikuma larseni sp. nov. can be distinguished from I. spiculosa by the colouration and pubescence (carapace with densest pubescence along margins vs. in subcentral part of the carapace); the new species has a uniformly pale abdomen vs. bicolorous in I. spiculosa (Fig. 2A, C cf. Fig. 1 ). The interdistance AME-AME is longer than AME-ALE in I. larseni sp. nov. and shorter in I. spiculosa . Since characters of I. spiculosa seem to be based on the juvenile or subadult specimens, the comparison of the copulatory organs remains impossible.

Description.

Female. NMSA-SPI-26895 (holotype).

Habitus: as in Fig. 2A, B . Colour in alcohol: carapace and chelicerae dark carmine red; maxillae, coxae I-IV and abdominal scuta light to intensely orange; palp and legs I-IV from femora to tarsi pale yellowish orange (leg I slightly darker than legs II-IV, with more noticeable difference between corresponding tibiae and metatarsi); sternum, labium and pedicel tube medium carmine red; abdomen very pale yellowish orange, dorsally with large slightly darker oval median marking; spinnerets yellowish white. Carapace and abdomen laterally covered with dense flattened and adpressed whitish pubescence. Measurements: TL 11.15. CL 4.81, CW 3.22, CyL 0.56 (0.43), Femur I L/W 2.29 (3.41/1.49). Carapace: with moderately coarse granulations (Fig. 3A ). Eyes (Fig. 3B, C ): AME 0.27, ALE 0.16, PME 0.13, PLE 0.13; AME-AME 0.16, AME-ALE 0.11, AME- PME 0.20, ALE-PLE 0.41, PLE-PME 0.18, PME-PME 0.31. Mouthparts: labium with slightly notched anterior edge (Ln; Fig. 4B ). Legs I-IV: tarsi with paired claw tufts of dense long setae and multipectinate paired claws each armed with 8-10 teeth (Fig. 7A ). Abdominal sclerites: short pedicel tube (Pt) widely funnel-shaped (Figs 4C , 5A, B ); small hexagonal dorsal shield (Ds) clearly separated from and not fused with lateral sclerotized extensions (Le; Fig. 5A ); epigastral plate (Eg) in intact specimen (before dissection) uniformly coloured, posterior part slightly concave; postgaster with one thin bow-shaped scutum (Fig. 4C ); posterior edge nearly straight. Spinnerets as shown in Fig. 7B .

Copulatory organs: as in Figs 5C-F , 6 . Endogyne weakly sclerotized (unlike partially heavy-sclerotized one in Palpimanus spp.); main supporting structure, wide trapezoidal endogynal fold (Rf), carries two lateral apophyses (La); membranous sacs of receptacles (Rs) bell-shaped, about as long as wide, each receptacle accompanied by brushes of fine threads (Ft) and approximately 7-8 grape-shaped glands (Gg), glands with stalks about as long as head, pore glands indiscernible (seems absent).

Leg measurements: female NMSA-SPI-26895 (male NMSA-SPI-26894 in brackets):

Male. NMSA-SPI-26894 (paratype).

Habitus: as in Fig. 2C, D . Colour in alcohol: as in female, but coxae I-IV evenly orange and tarsus I pale yellow, much lighter than metatarsus I. Measurements: TL 12.37. CL 5.78, CW 3.95, CyL 0.29, Femur I L/W 1.91 (4.23/2.21). Carapace: longer, with slightly coarser granulations than in female (Fig. 3D ). Eyes (Fig. 3E ): AME 0.28, ALE 0.18, PME 0.15, PLE 0.14; AME-AME 0.22, AME-ALE 0.12, AME-PME 0.34, ALE-PLE 0.46, PLE-PME 0.22, PME-PME 0.35. Mouthparts: as in female (see Fig. 4B ). Legs I-IV: metatarsi and tarsi armed with long ventral bristles as in female (Fig. 7C ); claw tufts and dentition as in female. Abdominal sclerites: epigastral scutum with clearly darkened book-lungs; postgaster with two large long subtriangular scuta (distinguishable in form from the corresponding scuta in other palpimanids), and two pairs of dot-like scuta (see Fig. 4E ).

Copulatory organs: Palp as shown in Figs 7D , 8. Femur nearly 3 times longer than wide, 1.5 times longer than cymbium and tibia, 2.3 times longer than patella; patella elongate, 1.5 times longer than wide; tibia elongate, not swollen, length/maximal width ratio ca. 1.6, subequal in length to cymbium, covered with dense and long whitish setae; cymbium about twice longer than wide; bulb droplet-shaped; tegulum as wide as long, lacking any processes (apophyses), retrolateral part of tegulum membranous; embolic division with 2 outgrowths: slightly bent spine-like chitinized embolic process (Ep), sigmoid in anterior view (see Fig. 8A), and membranous embolus (Em).

Variation.

In paratype females, the length of the carapace varies from 4.4 to 5.6 mm.

Habitat.

According to the collecting data, the specimens were obtained by sand sifting.

Distribution.

Known only from the type locality.

Note.

Since the only available male of Ikuma larseni sp. nov. was found partially damaged (probably when collected), we preferred to designate one of the better preserved females as the holotype.

Figures

Figure 1. Ikuma spiculosa, immature holotype specimen SAM-ENW-B 006293 A, B spider in dorsal and lateral view, respectively C carapace, dorsal D body, ventral. Scale bars: 1 mm.

Figure 2. Ikuma larseni sp. n., holotype female NMSA-SPI- 26895 (A, C) and paratype male NMSA-SPI- 26894 (B, D) A, B spider in dorsal view C, D same, lateral. Scale bars: 5 mm.

Figure 3. Ikuma larseni sp. n., holotype female NMSA-SPI- 26895 (A, C, D) and paratype male NMSA-SPI- 26894 (B, E) A, B carapace in dorsal view C, E eye group, clypeus and chelicerae, dorsal D same, lateral. Scale bars: 1 mm (A, D); 0.5 mm (B, C, E).

Figure 4. Ikuma larseni sp. n., holotype female NMSA-SPI- 26895 (A, C, D) and paratype male NMSA-SPI- 26894 (B, E) A, B cephalothorax and basal abdomen in ventral view C chelicerae, labium and maxillae, ventral D, E pedicel and abdominal scuta, ventral. Abbreviations: Eg epigastral plate; Le lateral extensions of scutum; Ln labial notch; Ps postgastral scuta. Scale bars: 1 mm (A, D); 0.5 mm (B, C, E).

Figure 5. Ikuma larseni sp. n., paratype female NMSA-SPI- 26881 A, B dissected, macerated and Chlorazol-tinted abdominal scuta in dorsal and ventral view, respectively C-F structures of endogyne, dorsal (inside). Abbreviations: Ds dorsal scutum; Eg epigastral plate; Ft fine threads; Gg grape shaped glands; La lateral apophyse of endogynal fold; Le lateral extensions of scutum; Pt petiolar tube; Rf basolateral fold of endogyne; Rs membranous sac like part of receptacle. Scale bars: 0.5 mm (A, B); 0.25 mm (C, D); 0.1 mm (E, F).

Figure 6. Ikuma larseni sp. n., paratype female NMSA-SPI- 26881 A-D structures of endogyne, close up dorsal (inside) view. Abbreviations: Eg epigastral plate; Ft fine threads; Gg grape shaped glands; La lateral apophyse of endogynal fold; Rf basolateral fold of endogyne; Rs membranous sac like part of receptacle. Scale bars: 0.1 mm.

Figure 7. Ikuma larseni sp. n., holotype female NMSA-SPI- 26895 (A, B) and paratype male NMSA-SPI- 26894 (C, D) A tarsus IV in retrolateral view B spinnerets, ventral C entire leg II, retrolateral D palpal segments from patella to cymbium, retrolateral. Scale bars: 0.5 mm (A, D); 0.25 mm (B); 1 mm (C).