Research Article
Research Article
Redescription of the poorly known genus Ikuma Lawrence, with synonymy and description of a new species from Namibia (Araneae, Palpimanidae)
expand article infoSergei Zonstein, Yuri M. Marusik§|
‡ Steinhardt Museum of Natural History, Tel-Aviv, Israel
§ University of Turku, Turku, Finland
| University of the Free State, Bloemfontein, South Africa
Open Access


The spider genus Ikuma Lawrence, 1938, endemic to Namibia, is rediagnosed and redescribed based on the characters both species originally included in the genus and of the newly described I. larseni sp. nov. A new synonymy is proposed: I. squamata Lawrence, 1938, described from a sole female is recognized a junior synonym of the type species I. spiculosa (Lawrence, 1927), based on a single juvenile. The currently described I. larseni sp. nov. differs from the generotype in the eye arrangement, structure of the abdominal scuta, and details of the colouration. The copulatory organs of both males and females belonging to Ikuma are studied, described and depicted for the first time. The previously known genus range confined to the far north of Namibia extends to the mid-western part of this country.


Afrotropic, Aranei, Namibia, Palpimaninae, spider, taxonomy


The small spider genus Ikuma was established by Lawrence (1938) to encompass two species: I. spiculosa (Lawrence, 1927) (transferred from Palpimanus Dufour, 1820) and I. squamata Lawrence, 1938. The genus was not diagnosed in detail, only briefly compared in the character of the body pubescence and of the eye arrangement with Palpimanus and Diaphorocellus Simon, 1893 (sub Iheringia Keyserling, 1891). The type species, I. spiculosa, has originally been recognised as based on a juvenile. The only known specimen of I. squamata, when described, was claimed to be an adult female; however, no evidence of this statement has been provided.

Many decades have passed since its description, and both the genus concept and the key generic characters of Ikuma have continued to be unclear. Platnick (1981) briefly reviewed the Palpimaninae and considered that this subfamily could be divided into two groups, each probably of the genus rank. Both these groups could be delimited by possessing an entire or divided abdominal scutum in the females. The species with an entire abdominal sclerite in the females he has undoubtedly assigned to Palpimanus. The question as to whether all of the remaining species also form a monophyletic group (for which, in his opinion, the name Ikuma would be available), Platnick intended to consider in a subsequent study which, however, has never been conducted and published.

The reason for Platnick (1981) considering the difference between Palpimanus and Ikuma as based chiefly on the aforenoted criterion remains uncertain. Lawrence (1938), when establishing Ikuma, did not textually describe the abdominal sclerites in Ikuma, and Platnick himself had not noted any of the two known species of Ikuma within the studied material. Nevertheless, this assumption was then mentioned by Dippenaar-Schoeman and Jocqué (1997), who cited the mentioned review, refraining from their own comments. Until now, Ikuma has been thus treated as a once described and then completely forgotten taxon with dubious characters.

The present attempt to find criteria for reliably distinguishing between the genera of Palpimaninae was triggered by two interdependent events. First, among the studied palpimanids from Namibia, we have revealed a few palpimanine spiders that looked completely different to Palpimanus spp. On the other hand, by our request we have received a fortunate opportunity to look, albeit remotely, at the holotype of Ikuma spiculosa. As a result, we identified the noted specimens as certainly belonging to Ikuma and representing a yet-undescribed species. The type series of this new congener is diagnosed, described and illustrated herein.

Materials and methods

Used museum acronyms

DNMNH Ditsong National Museum of Natural History, Pretoria, South Africa;

KZNM KwaZulu-Natal Museum, Pietermaritzburg, South Africa;

MNB Museum für Naturkunde, Berlin, Germany;

NCA National Collection of Arachnida, ARC-Plant Protection Research Institute, Pretoria, South Africa;

NHML Natural History Museum, London, UK;

NMSA Natal Museum, the former abbreviation for KZNM, used in the labels;

RMCA Royal Museum for Central Africa, Tervuren, Belgium;

SAM Iziko South African Museum, Cape Town, South Africa;

SMNH Steinhardt Museum of Natural History, Tel Aviv, Israel.

Comparative material used in this study

Palpimanus Dufour, 1820: males and females of P. gibbulus Dufour, 1820 from La Palma, Mallorca (NHML), P. schmitzi Kulczyński, 1909 and P. simoni Kulczyński, 1909 from different localities in Israel (SMNH); the types of P. namaquensis Simon, 1910 from South Africa (MNB 13859) and P. nubilus Simon, 1910 from Namibia (MNB 13860).

Diaphorocellus Simon, 1893: the types of D. isalo Zonstein & Marusik, 2020 (RMCA ARA 200305) and D. jocquei Zonstein & Marusik, 2020 (RMCA ARA 201275), all from Madagascar; males and females of D. biplagiatus Simon, 1893 from Beaufort-West, South Africa (NCA 2008/4675) and D. rufus (Tullgren, 1910) from Mkomazi, Tanzania (RMCA ARA 215487).

Photographs were taken using an Olympus SZX16 stereomicroscope with a Canon EOS 7D (Turku) or Canon EOS 80D (Tel Aviv) camera and prepared using the Helicon Focus 7.6.2 Pro software ( Measurements were taken through the above-mentioned stereomicroscope to an accuracy of 0.01 mm. All measurements are given in millimetres. The maximum length of the clypeus along the midline was measured from the anterior edge to the perpendicular line connecting the anterior edge of both AME; the smaller lateral clypeus length, measured from the anterior edge of ALE and the closest point of the anterior clypeus edge, follows the maximum clypeus length, being enclosed in brackets. The length of the sternum was measured along a straight line between the posterior tip of the sternum and the hindmost part of the labium. Lengths of leg and palp segments were measured on the dorsal side, with lengths of every measured segment from the midpoint of the anterior margin to the midpoint of the posterior margin.

Illustrations of the dissected vulva, placed into a small Petri dish filled with a 85% lactic acid, were made after cleaning the object in 10% potassium hydroxide aqueous solution for several hours and exposing it for a few minutes in an alcohol solution of Chlorazol Black.


AER anterior eye row;

ALE anterior lateral eye;

AME anterior median eye;

CL carapace length;

CW carapace width;

CyL clypeus length;

MOQ median ocular quadrangle;

PER posterior eye row;

PLE posterior lateral eye;

PME median lateral eye;

TL total body length in dorsal view.

Other abbreviations used are encoded in the text and in the captions.


Palpimanidae Thorell, 1870


Since Platnick (1975), the family is considered consisting of three subfamilies: the mostly Paleotropical Chediminae Simon, 1893, the purely Neotropical Otiothopinae Platnick, 1975, and the nominative subfamily Palpimaninae. The distributional peculiarities of the latter subfamily are considered below.



This subfamily differs from the Otiothopinae by possessing accessory terminal sclerites in the male bulb (which are absent in the males belonging to the latter subfamily; see Platnick 1975). The Palpimaninae can be distinguished from the Chediminae in having eight eyes with widely spaced ALE and PLE vs. two, six or eight eyes with contiguous or lacking ALE and PLE in the chedimine spiders (Zonstein and Marusik 2017). The subfamily is distributed in the Old World, where its range is limited to the Mediterranean, Sahara-Sind region (including Middle East, Gujarat and Central Asia), and the mainland Sub-Saharan Africa. The record of Palpimanus argentinus Mello-Leitão, 1927 in South America, based only on the types, has not been confirmed by later field studies, and may refer either to a sole introduced species (Platnick 1975) or, even more likely, to the incorrectly interpreted collection data (Zonstein and Marusik 2017). The Palpimaninae are divided between two sharply uneven groups of the genus rank: a species-rich Palpimanus Dufour, 1820, with 38 named species distributed throughout the entire subfamily range (WSC 2022), and a small Namibian genus Ikuma Lawrence, 1938, embracing only two species.

Ikuma Lawrence, 1938

Ikuma Lawrence, 1938: 217.

Type species

Palpimanus spiculosus Lawrence, 1927, by original designation.

Emended diagnosis

Ikuma (I.) well differs from Palpimanus (P.) in the shape of the carapace (anteriorly narrowed, ovoidal and gently elevated from the edges to the domed central part in I. vs. round-oval and steeply edged in P.), in the clypeus (inclined in I., vertical in P.), and in the shape of the sternum (longer and visually narrower, ending posteriorly behind coxae IV in I. vs. shorter, looking subrounded, and ending posteriorly at the axes of coxae IV in P.). The whitish adpressed pubescence on the dorsal and lateral surface of the carapace is much longer and denser in I. (where it is present also on the dorsal abdomen) than in P. (where a similar pubescence is much shorter and sparser, and confined only to the carapace). The embolus is small, fragile and membranous in I. vs. relatively large, branched and with partially sclerotized structures in P. The adult females of these genera can be distinguished by the structure of the endogyne, either possessing (P.) or lacking (I.) heavily sclerotized parts.


Medium-sized to large palpimanids with carapace length ranging 4.4–5.8 in adult specimens. Dorsal body (both carapace and abdomen) densely covered with pale adpressed pubescence (Figs 1, 2); most sclerotized parts (carapace, chelicerae, sternum and abdominal scuta) finely granulated, as in Figs 14, 5A, B. Carapace (Figs 1C, 3A, B) narrowed anteriorly, ovoidal, with raised central part gently sloping toward edges and elevated hump between eye group and thoracic fovea. Short T-shaped thoracic fovea deeply excavated, foveal sulci poorly discernible. Clypeus moderately long. Eight eyes (Figs 1C, 3); AME largest, other eyes relatively smaller and subequal in size. AER recurved; PER nearly straight and noticeably wider than AER; both rows form wide trapezoidal figure. MOQ slightly wider than long. Chilum inconspicuous. Chelicerae about twice longer than clypeus; stridulatory ridges absent; cheliceral fang serrated; cheliceral furrow armed with several (5–6 in Ikuma larseni sp. nov.) peg teeth. Maxillae triangular. Labium long and narrow, notched anteriorly (Fig. 4B). Sternum densely granulated, covered with fine short hairs and extending backward between coxae IV (Figs 1D, 4A, D).

Figure 1. 

Ikuma spiculosa, immature holotype specimen SAM-ENW-B006293 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).

Palps short, legs I–IV moderately long. Leg formula: 4132. Leg I robust, with considerably swollen and laterally flattened femur, with patella longer that tibia, and tarsus longer than metatarsus (Figs 1B, 2B, D). Tibia and metatarsus I with wide and dense prolateral scopula. Leg tarsi II–IV relatively short; two tarsal claws narrow and provided with several short teeth. Claw tufts well-developed (as in Fig. 7A).

Abdomen fusiform, in unsclerotised part with contrasting dorsal pattern or uniformly pale coloured. Abdominal scuta conforming a rather short pedicel tube; dorsal portion of scutum narrow, small and narrowly separated from both pedicel tube and large scoop-like ventral portion. Small spinneret group set on low mound (see Fig. 7B). AMS small, cylindrical, two-segmented; PMS and PLS reduced to a few sessile spigots in females and absent in males.


Ikuma includes two species: I. spiculosa (Lawrence, 1927) and I. larseni sp. nov.


The genus is currently known only from Namibia.

Ikuma spiculosa (Lawrence, 1927)

Fig. 1

Palpimanus spiculosus Lawrence, 1927: 23 (j).

Ikuma spiculosa: Lawrence 1938: 217.

Ikuma squamata Lawrence, 1938: 217, fig. 3 (j), syn. nov.


Palpimanus spiculosus: Holotype: juvenile, Namibia, Oshikoto Region, Namutoni, 18°48.5'S, 16°56.5'E, 1100 m, unspecified collector, most seemingly G.C. Shortridge (see Thomas 1926), 29.viii.1923 (SAM-ENW-B006293), seen from the full-colour and high-resolution macro-photographs kindly provided by N. Larsen. Ikuma squamata: Holotype: juvenile (or subadult specimen), the same collection data as the preceding but Ikuma (Ekuma) River Valley, approximately 18°34'S, 16°00'E, 1100 m, further details uncertain, presumably deposited in the Transvaal Museum (currently DNMNH); however, it was not found there.


There are a number of significant differences between Ikuma spiculosa and I. larseni sp. nov. It concerns the coloration of the abdomen (contrastingly bicolorous vs. uniformly pale), position of the appressed pubescence on the carapace (mostly subcentral vs. sublateral), and the relative length of interdistance AME-AME (longer than AME-ALE vs. shorter than AME-ALE).

Description (based on seemingly non-adult specimens)

The species was in fairly sufficient details described by Lawrence (1927, 1938). See also Fig. 1.


Oshikoto Region in northern Namibia.


The aerial distance between the type localities of Ikuma spiculosa and I. squamata, Namutoni and Ikuma River, is less than 100 km. Both are situated at the same elevation, and they adjoin the same saline depression Etosha Pan. The holotype specimens of the two species do not differ in the peculiarities and details of their pubescence and overall colouration. Judging from the original descriptions, these types can be distinguished only by their size (TL 3.6 in I. spiculosa vs. 5.5 in I. squamata). Applied to the difference in the body size between these specimens and the type series of I. larseni sp. nov. (TL 10.7–12.1), it may simply indicate that these non-adult specimens can be, respectively, a younger and an elder instars belonging to the same species. Hence, Palpimanus spiculosus Lawrence, 1927 is considered here a senior synonym of Ikuma squamata Lawrence, 1938, syn. nov.

Ikuma larseni sp. nov.

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


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.


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).


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.


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, AMEPME 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.

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).

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).

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).

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

Femur Patella Tibia Metatarsus Tarsus Total
Palp 1.09 (1.18) 0.45 (0.51) 0.85 (0.77) 0.65 (0.78) 3.04 (3.24)
Leg I 3.41 (4.23) 3.03 (3.62) 2.72 (3.16) 1.41 (1.57) 1.55 (1.74) 12.12 (14.32)
Leg II 2.68 (3.37) 1.61 (2.01) 1.93 (2.35) 1.29 (1.50) 0.88 (0.97) 8.39 (10.20)
Leg III 2.98 (3.42) 1.59 (1.93) 2.06 (2.42) 1.75 (1.81) 0.95 (1.46) 9.33 (11.04)
Leg IV 4.28 (4.48) 1.99 (2.28) 3.11 (3.32) 2.39 (2.87) 1.10 (1.52) 12.87 (14.47)

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).

Figure 8. 

Ikuma larseni sp.n., paratype male NMSA-SPI-26894, cymbium and palpal bulb A in frontal view B same, ventrofrontal C, D same, retrolateral. Abbreviations: Em embolus; Ep embolic process. Scale bars: 0.25 mm.


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


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


Known only from the type locality.


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.


We thank Norman Larsen (SAM), Kirstin Williams and Matabaro Ziganira (KZNM), Ansie Dippenaar-Schoeman and Petro Marais (NCA), Janet Beccaloni (NHML), Arnaud Henrard and Rudy Jocqué (RMCA), and Jason Dunlop (MNB), for providing us with macro-photographs of the holotype of Ikuma spiculosa and loaning us the material used for this study. We also thank Charles Haddad and an anonymous reviewer for their valuable comments and recommendations. Special thanks go to Ilari Sääksjärvi and Seppo Koponen (Zoological Museum, University of Turku) for providing us with museum facilities. This study was supported in part by the Ministry of Absorption, Israel.


  • Dippenaar-Schoeman AS, Jocqué R (1997) African Spiders: An Identification Manual. Plant Protection Research Institute Handbook 9, 392 pp.
  • Lawrence RF (1927) Contributions to a knowledge of the fauna of South-West Africa V. Arachnida. Annals of the South African Museum 25(1): 1–75.
  • Lawrence RF (1938) Transvaal Museum Expedition to South-West Africa and Little Namaqualand, May to August 1937. Spiders. Annals of the Transvaal Museum 19: 215–226.
  • Platnick NI (1975) A revision of the palpimanid spiders of the new subfamily Otiothopinae (Araneae, Palpimanidae). American Museum Novitates 2562: 1–32.
  • Platnick NI (1981) A review of the spider subfamily Palpimaninae (Araneae, Palpimanidae). Bulletin - British Arachnological Society 5(4): 169–173.
  • Thomas O (1926) On Mammals from Ovamboland and the Cunene River, obtained during Capt. Shortridge’s third Percy Sladen and Kaffrarian Museum Expedition into South-West Africa. Proceedings of the Zoological Society of London 1926(1): 285–312.
  • World Spider Catalog (2022) World Spider Catalog. Natural History Museum Bern, version 23.5. [accessed on 4.vii.2022]
  • Zonstein SL, Marusik YM (2017) Descriptions of the two-eyed African spider genera Chedimanops gen. n. and Hybosidella gen. n. (Araneae, Palpimanidae, Chediminae). African Invertebrates 58(1): 23–47.
login to comment