Nemesia decaei, Zonstein, 2019

Zonstein, Sergei L., 2019, New data on the spider genus Nemesia in Algeria (Araneae: Nemesiidae), Israel Journal of Entomology (Oxford, England) 49 (1), pp. 69-130 : 94-99

Nemesia decaei n. sp.

( Figs 66–81)

LSID: urn:lsid:zoobank.org:act:90664DCF-74B3-4C24-89D3-D79B6EF7367F .

Etymology: The species is named in honour of the prominent Dutch arachnologist Arthur Decae, who published a number of studies devoted to the taxonomy and ecology of Nemesia and described several new species in this genus.

Diagnosis: Male of this new species differs from most male congeners in having a very long and hardly curved embolus (more than 3 times as long as the tegulum). Only the males of two so far undescribed Tunisian Nemesia spp. and N. almoravida n. sp. possess comparably long and similarly extended and tapered emboli; however, unlike N. decaei n. sp., these emboli are either noticeably shorter, or more strongly curved and bent or narrower at their base ( Figs 72, 73 cf. Figs 37–39, 148–150). Females of N. decaei n. sp., with their long and multiple twisted stalks of the spermathecae, can be easily distinguished from females of most other species of Nemesia . Similarly shaped spermathecae are found in several undescribed Nemesia species from Tunis; however, even in this case they clearly differ in shape from the structure characteristic for N. decaei n. sp. ( Figs 79, 80 cf. Figs 154, 155, 157).

Description: Male (holotype MNHN 6163/AR4486; Fig. 66): Body length 13.40.

Colour in alcohol: carapace (with slightly darker stellate pattern), leg and palp segments medium to dark ochre brown; stellate pattern of carapace and chelicerae slightly darker reddish brown; clypeus paler, brownish yellow; eye tubercle brownish black; sternum, labium, maxillae, and leg coxae ventrally light yellowish orange; ventral surface of abdomen and spinnerets light yellowish brown; abdomen dorsally light ochre brown with darker brown pattern consisting of diffuse interrupted median strip and several pairs of narrow lateral chevrons.

Cephalothorax dorsally and ventrally as in Figs 67 and 69. Carapace 5.58 long, 4.28 wide. Eye tubercle as in Fig. 68. Eye diameters and interdistances: AME 0.17(0.23), ALE 0.24, PLE 0.18, PME 0.12, AME–AME 0.16(0.10), ALE–AME 0.10(0.07), ALE–PLE 0.12, PLE–PME 0.04, PME–PME 0.44. Chelicerae: each furrow with 6 promarginal teeth and ca. 15 mesobasal denticles; rastellum with 4–5 large spines in front of cheliceral fang. Labium 0.52 long, 0.99 wide. Sternum 2.81 long, 2.32 wide. Each maxilla with 3 small cuspules confined to inner maxillary heel.

Palp and leg structures. Tibia and metatarsus I as in Fig. 70. Spines (tarsi I–IV aspinose). Palp: femur d1–1–2, dp1; patella p1; tibia with 4 heavy curved dorsoapical spines; cymbium with about 15 short dorsal spines. Leg I: femur d1–1–1–1–2, pd1– 0–1–1, rd1–1–1–1; patella p1–1; tibia p1–1, r1–1, pv0–1–M; rv1–1–1; metatarsus p1–1, r1–1–1, v1–1–2. Leg II: femur d1–1–1–1–2, pd1–0–1–1, rd1–1–1–1; patella p1–1; tibia p1–1, r1–1, v1–2–2; metatarsus p1–1, r1–1–1, v1–1–2. Leg III: femur d 1–1–1–1–2, pd1–1–1, rd1–1–1; patella p1–1, r1; tibia d1–1–1, p1–1–1, r1–1, v2–2–3; metatarsus d1–1–1–1, p1–1–1, r1–1–1–1, v2–2–3; Leg IV: femur d 1–1–1–1–2, pd1–1–1–1, rd1–1–1–1; patella p1, r1; tibia p1–1–1, r2–1–1, v3–2–3; metatarsus d1–1–1, p1–1–1, r1–1–1, v2–2–3. Metatarsal preening combs absent. Scopula entire on metatarsus I, and tarsi I and II; entire and distal on metatarsus II; divided with setae on tarsus III, absent on tarsus IV. Trichobothria: 2 rows of 9–10 in each row on tibiae, 13–15 on metatarsi, 14–15 on tarsi, 10–11 on cymbium. Paired claws of tarsi I–IV with 8–10 teeth in each row.

Leg and palp measurements:

Palp

I II III IV

Femur 2.48 4.19 4.04 3.84 5.08

Patella 1.26 2.61 2.23 2.13 2.65

Tibia 1.68 2.72 2.61 2.61 4.97

Metatarsus – 2.90 2.95 3.35 4.52

Tarsus 0.95 1.98 1.91 2.08 2.51

Total 6.37 14.40 13.74 14.01 19.73

Copulatory organs. Palpal tibia moderately short, with few heavy dorsoapical spines ( Figs 71, 72). Palpal organ with long, slightly curved and gradually tapering embolus ( Figs 72, 73).

Spinnerets as in Fig. 74. PMS: length 0.36; diameter 0.20. PLS: maximum diameter 0.54; length of basal, medial and apical segments 0.71, 0.26, 0.14, respectively; total length 1.11; apical segment domed.

Female (paratype MNHN 6163/AR4486; Fig. 75): Body length 19.30.

Colour in alcohol: as in male, but clypeus and margins of carapace paler, while chelicerae and dorsal pattern on carapace and on abdomen darker and more contrast than in male.

Cephalothorax dorsally and ventrally as in Figs 76 and 78, respectively. Carapace 7.32 long, 5.66 wide. Eye tubercle as in Fig. 77. Eye diameters and interdistances: AME 0.19(0.27), ALE 0.39, PLE 0.34, PME 0.19, AME–AME 0.26(0.20), ALE– AME 0.16(0.13), ALE–PLE 0.13, PLE–PME 0.04, PME–PME 0.61. Chelicerae: each furrow with 6 promarginal teeth and 15–16 mesobasal denticles; rastellum with 6 heavy and 12–15 smaller cone teeth in front of cheliceral fang and on mound. Labium 0.72 long, 1.35 wide. Sternum 4.06 long, 2.94 wide. Each maxilla with 5 cuspules confined to inner maxillary heel.

Palp and leg structures. Spines (palpal tarsus and tarsi I–II with 6–11 small ventroapical spines; patellae I–II and IV, and tarsi III–IV aspinose). Palp: femur d1–1–1–2; patella p1; tibia v2–2–3. Leg I: femur d1–1–1–1; tibia v1–1–2; metatarsus v2–1(0)–3. Leg II: femur d1–1–1–2; tibia v2–2–3; metatarsus v3–2–3(4). Leg III: femur d1–1–1–2, pd1–1–1, rd1–1–1; patella p1–1; tibia p1–1, r1–1, v2–2–2; metatarsus p1–1–1, pd1–1, r1–1–1, v2–2–3. Leg IV: femur d 1–1–1–1–2, pd1–1; patella p1–1; tibia r1–1, v2–2–2; metatarsus p1(0)–1–1, r1–1–1, v2(1)–2–3. Metatarsal preening combs absent. Scopula entire, ventral and prolateral on metatarsi I and II; ventral, prolateral and widely divided on palpal tarsus and tarsi I and II; elsewhere absent. Trichobothria: 2 rows of 8–9 in each row on tibiae, 10–11 on metatarsi, 11–12 on tarsi, 9 on palpal tarsus. Palpal claw with 3 teeth on promargin. Inner/outer margins of PTC I–II and PTC III–IV with 5–7/5–7 and 1–3/5–6 teeth, respectively.

Leg and palp measurements:

Palp

I II III IV

Femur 3.31 4.66 4.19 3.98 5.35 Patella 1.82 2.93 2.56 2.23 3.39 Tibia 1.99 3.00 2.63 2.25 5.17 Metatarsus – 2.56 2.43 2.84 4.47

Tarsus 2.42 1.67 1.67 1.83 1.91

Total 9.54 14.82 13.48 13.13 20.29

Copulatory organs. Spermathecae long, with slightly tapered bases, spiraled stalks

(twisted twice) and slightly dilated heads ( Figs 79, 80).

Spinnerets as in Fig. 81. PMS: length 0.56; diameter 0.33. PLS: maximum diameter 0.75; length of basal, medial and apical segments 1.29, 0.47, 0.19, respectively; total length 1.95; apical segment domed.

Variation: Carapace length in females varies from 6.7 to 8.2 mm. Darker dorsal pattern of the abdomen is almost uniform in all specimens.

Holotype: ♂ Algeria: Oran Province: surroundings of Oran (35°42′N 0°38′W), no other data (MNHN 6163/AR4486).

Paratypes: Algeria: Oran Province: 6♀, collected together with holotYpe (MNHN 6163/AR4486) .

Distribution: Known only from the type locality.