Misumena bicolor Simon, 1875

Bach, Alexander, Lauterbach, Stephan, Astrin, Jonas J., Thorns, Hans-Jürgen & Bauer, Tobias, 2024, A master in disguise? The rediscovery of Misumena bicolor Simon, 1875 (Araneae: Thomisidae), Zootaxa 5529 (1), pp. 175-185 : 177-179

Misumena bicolor Simon, 1875

Figs 1A1–A5, 2A–B, 3, 4A

Misumena bicolor Simon, 1875: 246 , pl. 7, f. 2 (holotype male from FRANCE: Corsica [Muséum national d’histoire naturelle, Paris], examined by Lehtinen 2004 and Breitling et al. 2016). Lehtinen 2004: 171, f. 86–87; Breitling et al. 2016: 70, f. 11.

Other material examined. ITALY: Sardinia: Bolotana , 40.353N, 8.911E, 990 m, 1 male, 12 June 2022, A. Bach leg., sweep netted in a wet meadow near Riu Ilde . GERMANY: Bavaria: Deggendorf, Westlicher Stadtgraben 50, 1 male, 2 June 2022, HJ Thorns leg., collected by hand (ZFMK-TIS-76343; BOLD-ID: LIBBB218-23) .

Comparative material of M. vatia . GERMANY: Hesse: Usingen, close to Eschbacher Klippen , 50.3638N, 8.5381E, 381 a.s.l., 2 males, 2 females, 8 June 2017, leg. S. Lauterbach. North Rhine-Westphalia: Bestwig, Ostenberg , old quarry, 51.3505N, 8.4036E, 419 m a.s.l., 7 males, 2 females, leg. S. Lauterbach. Baden-Württemberg: Elfmorgenbruch by Karlsruhe , forest clearing, 49.0097N, 8.4547E, 1 male, 23 May 2023, leg. T. Bauer (Coll. T. Bauer) .

Diagnosis. Differentiated from other species of the genus by the combination of the orange opisthosoma lacking any longitudinal stripes as well as dark lateral patterns in combination with a less coiled embolus compared to M. vatia . In M. vatia , the embolus is much more strongly coiled, with the distal part nearly in parallel position to the sides of the cymbium and the tip at a 90° angle (Figs 1 B1, B2, B4)), while in M. bicolor the distal part and the tip point, more or less, in the same direction (Figs 1 A1, A2, A5). In addition, the RTA of M. vatia bears an additional hump in the basal part (Fig 1 B3), which is missing in M. bicolor . The position of the spermophor in the basal part of the embolus differs as well. While the spermophor is positioned more horizontally in M. vatia , in M. bicolor it enters the embolus in a transversal position.

Description. Male (from Sardinia, in ethanol): Pr length 1.3, Pr width 1.35, Op length 1.9, Op width 1.35. The prosoma of M. bicolor is black in live specimens, with a lighter area behind the fovea and the eyes. When preserved in ethanol, the prosoma becomes dark reddish-brown. In contrast, the prosoma of M. vatia features a light, often yellow, longitudinal stripe. The opisthosoma of M. bicolor is a light yellowish tone, covered with conspicuous, short spines, and lacks any longitudinal lines or dark lateral patterns, which sharply contrasts with the opisthosoma of M. vatia . The femora of the first pair of legs are prominently dark in color, while the remaining segments display an anterior reddish-brown hue, with a gradual brightening towards the posterior regions Left leg measurements: I. coxa 0.40; trochanter 0.30; femur 2.10; patella 0.70; tibia 1.75; metatarsus 1.50; tarsus 0.50; total length 7.25 II. 0.40; 0.25; 2.05; 0.65; 1.70; 1.45; 0.80; 7.30; III. 0.30; 0.15; 0.90; 0.40; 0.70; 0.55; 0.40; 3.40; IV. 0.35; 0.20; 0.90; 0.40; 0.70; 0.60; 0.40; 3.55.

Female: Unknown.

Comment. Our specimens ( Figs 2A–B , 3 ) are consistent with the somatic description provided by Simon (1875). However, concerning the palp, Simon’s description merely notes that it is disc-shaped and of a reddish coloration. Similarly, Lehtinen’s (2004) description is relatively concise, mentioning only the differences between M. bicolor and M. vatia with respect to a stronger coiled embolus and details in RTA morphology. However, Breitling et al. (2016) highlighted the important difference that the embolus in M. bicolor is less coiled than in M. vatia , a characteristic which was also observed in both of our specimens (Fig. 1 A5).

Molecular analyses. In the Neighbor Joining tree ( Fig. 5 ), the COI sequence of the Misumena bicolor male from Germany clearly falls outside the M. vatia cluster. The genetic distances between M. bicolor and M. vatia range from 6.4 to 8.0% (uncorrected p -distance when comparing full sequences of M. vatia in the dataset, over a length of 653 bp). Intraspecific distances in M. vatia range from 0.0 to 2.3%. This provides strong evidence in favor of allocating the specimens from Germany (and Corsica) to a species distinct from M. vatia . A single sequence of a potentially juvenile “ M. vatia ” -specimen from Corsica on BOLD (Process ID LPRCS004-19) is nearly identical to our sequence and represents M. bicolor (BIN/Barcode Index Number BOLD:AEC4584) as well.

Genetic distance of the M. bicolor specimens to the outgroup Spiracme striatipes is ca. 12% (same for M. vatia ) and to Misumena spinifera ca. 9%. Misumena vatia is separated from M. spinifera by around 10%.

FIGURES 1 A1–5, B1–5. A1–A5 Misumena bicolor , male from Sardinia; B1–B5 Misumena vatia , male from Germany. A1, B1 Palp, ventral, scale: 0.2 mm; A2, B2: Palp without tibia, lateral, scale: 0.1 mm; A3, B3: RTA lateral, scale: 0.1 mm; A4, B4: Apical tip of RTA, scale: 0.05 mm; A5, B5: Embolus ventral, scale: 0.05 mm.

Photographic records from naturalist networks. In addition to the two photo-based records from Germany in Breitling et al. (2016), fourteen other photo-records from Germany, mainland France, Italy and Austria were identified. Links and coordinates from all sites are given in the supplement table.Photographic evidence of M. bicolor in mainland Europe is available from west or north of the Alps. The westernmost photographic record comes from the French commune Astaffort in the department of Aquitaine, while the northernmost locality is in the Solling, a German low mountain range in Lower Saxony ( Fig. 6 ).

Figures

FIGURES 2A–D. Habitus of preserved male specimens of Misumena bicolor from Sardinia (Italy) (A, B) and M. vatia from Germany (C, D) in dorsal (A, C) and ventral (B, D) view. Scales: 2.00 mm.

FIGURES 3A–B. In vivo habitus of Misumena bicolor from Germany in dorsal (A) and lateral (B) view.

FIGURE 5. Neighbor Joining Tree including the COI-Sequence of Misumena bicolor (from Germany; ZFMK-TIS-76343).

FIGURE 6. Collected (yellow circles) and photographic records (turquoise circles), based on images and literature, of Misumena bicolor in the Western Palaearctic. The collected specimen from Tunisia is lost (Pavesi 1880).