Leiobunum longipes Menge, 1854

Dunlop, Jason & Mitov, Plamen, 2009, Fossil harvestmen (Arachnida, Opiliones) from Bitterfeld amber, ZooKeys 16, pp. 347-375 : 369

Leiobunum longipes Menge, 1854

Figs 30 , 33

Synonymy. See Dunlop (2006, pp. 172-173).

Holotype. Probably originally in Danzig (= Gdańsk , Poland), current whereabouts unknown (see also Dunlop 2006), from Baltic amber (Palaeogene, Eocene); precise locality unclear.

Additional material. MB.A. 1662 (series 15/10, provisionally labelled “Gyantinae cf. Amilenus ” but not in fact referable to this genus; see above), probably from the site of the Goitsche open-cast Mine near Bitterfeld, Sachsen-Anhalt, Germany ; Palaeogene (Oligocene: Chattian).

Description. MB.A. 1656 ( Figs 30 , 33 ) is an almost complete specimen of a fairly large harvestman in dorsal view. Body length: 2.1 mm; width of prosoma and opisthosoma 1.3 mm. Carapace procurved anteriorly, with clear division into promeso- and metapeltidium, and centrally located ocular tubercle. Length of ocularium 0.225 mm, width 0.275 mm, distance from ocular tubercle to front of prosoma 0.25 mm. Opisthosoma covered by scutum parvum bearing in places slightly granular ornament; posterior region and any segmentation here obscure. Body covered with small black dots and a subcuticular, silvery pigment. Chelicerae equivocal. Pedipalps short and pediform, but details lacking. Legs relatively complete, at least proximally, elongate and slender. Leg 1 femur length 1.83 mm, patella, 0.24. Leg 2 only known from incomplete femora. Leg 3 complete with podomere lengths (in mm) of femur, 1.79; patella, 0.45; tibia, 1.52; metatarsus, 1.86, tarsus, 3.20. Tarsus divided into 24 individual elements, becoming shorter distally, and ending in a single claw (apotele). Leg 4 only known from incomplete femora.

Remarks. Leiobunum longipes Menge, 1854 is present in both Baltic and Bitterfeld amber. Apparently quite common in Baltic amber ( Staręga 2002), this fossil is fairly large compared to the other Bitterfeld finds. Nevertheless, it is probably still only a juvenile, although we see nothing which differentiates it from the species known from Baltic amber.

Figures

Figures 27-30. 27 Fossil?Lacinius erinaceus Staręga, 1966, MB.A. 1661, from Bitterfeld amber (Palaeogene: Oligocene) 28-29 Recent male Lacinius erinaceus Staręga, 1966 (Holotype) in dorsal and lateral view for comparison, revealing an almost identical morphology to the amber fossil 30 Leiobunum longipes Menge, 1854 from Bitterfeld amber, MB.A. 1662. Scale bars equal 1.0 mm.

Figures 31-33. Camera lucida drawings of the specimens shown in 27 and 30. 31?Lacinius erinaceus Staręga, 1966, MB.A. 1661 32 the same detail of ocularium and its spination 33 Leiobunum longipes Menge, 1854, MB.A. 1662. Both from Bitterfeld amber (Palaeogene: Oligocene). Scale bars equal 1.0 mm (31, 33).