Mesopsalis oblongus, Bartel & Dunlop & Giribet, 2023

Bartel, Christian, Dunlop, Jason A. & Giribet, Gonzalo, 2023, An unexpected diversity of Cyphophthalmi (Arachnida: Opiliones) in Upper Cretaceous Burmese amber, Zootaxa 5296 (3), pp. 421-445 : 425

Species Mesopsalis oblongus sp. nov.

Fig. 2

urn:lsid:zoobank.org:act:A0B0F3B3-97F6-47AB-B452-AA4F3E05D6E9

Holotype. Specimen MB.A.4456, ex coll. Jörg Wunderlich, K 84.

Type locality. Myanmar, Hukawng Valley; Burmese amber. Upper Cretaceous (Lower Cenomanian).

Etymology. Latin adjective “oblongus” (= elongated), referring to the elongated ozophores of the holotype.

Diagnosis. As for the genus.

Description. Body oval and markedly subtriangular in profile at the anterior end; total L 3.50, maximum prosomal W behind ozophores 1.53, maximum opisthosomal W 1.90. Prosoma with a tuberculate-microgranular surface. Relatively thin and long conical ozophores in type 2 position ( Fig. 2C ). L of ozophores 0.31, W at base 0.14, distance between base of ozophores 1.11. Eyes present anterior to ozophores. Eye lenses surrounded by small tubercles ( Fig. 2A ). Chelicerae relatively small and at least granular on basal segment; basal segment L 0.55, median segment L 0.45, distal segment L 0.25. Pedipalps very small and thin; pedipalp length: fe 0.61, pa 0.23, ti 0.32, ta 0.37. Legs relatively short and somewhat granular; leg tarsi not subdivided, bearing a single smooth claw and numerous setae; tarsus IV without adenostyle; coxa I free, coxae II–III medially fused; leg lengths: I tr 0.28, fe 0.81, pa?, ti 0.58, mt 0.25, ta 0.44; II tr 0.36, fe 0.83*, pa 0.20, ti 0.47, mt 0.20, ta 0.50, total 2.56; III tr 0.31, fe 0.69, pa 0.30, ti 0.36, mt 0.22, ta 0.47, total 2.35; IV tr 0.25, fe 0.83, pa 0.39, ti 0.53, mt 0.20, ta 0.64, total 2.84. Opisthosomal sternal sulci mostly straight and parallel. Gonostome subcircular, W 0.27, L 0.24. Spiracles difficult to determine, presumably C-shaped. Anal plate elliptical and unmodified, W 0.37, L 0.14 ( Fig. 2D ).

Figures

FIGURE 2. Mesopsalis oblongus gen. et sp. nov., female holotype (MB.A.4456).A. Camera lucida drawing of whole specimen, dorsal view. B. Micro-CT scan of whole specimen, dorsal view. C. Same, lateral view. D. Same, ventral view. Abbreviations: ap, anal plate; ch, chelicerae; ey, eye lens; fe, femur; mt, metatarsus; oz, ozophore; pa, patella; pp, pedipalp; ta, tarsus; ti, tibia; tr, trochanter; legs numbered from I–IV. Scale bars equal 1 mm (A) and 0.5 mm (B–D).