Dicranopalpus ramiger ( Koch & Berendt, 1854 )

Dunlop, Jason & Mitov, Plamen, 2009, Fossil harvestmen (Arachnida, Opiliones) from Bitterfeld amber, ZooKeys 16, pp. 347-375 : 361-364

Dicranopalpus ramiger ( Koch & Berendt, 1854)

Figs 15-19

Synonymy. See Dunlop (2006: 170).

Holotype. MfN, Berendt collection, repository number 7250, from Baltic amber (Palaeogene, Eocene); precise locality unclear.

Additional material. MfN, MB.A. 1657 (also bears label “Ser. 12/14) and MB.A. 1658 (also bears label “Ser. 8”), from Bitterfeld amber, probably from the site of the Goitsche open-cast Mine near Bitterfeld, Sachsen-Anhalt, Germany; Palaeogene (Oligocene: Chattian).

Description. MB.A. 1657 ( Figs 15 , 17 ) is a fairly complete specimen in dorsal view. Body oval to quadrate, length 1.22 mm, maximum width 0.90 mm. Prosoma with semicircular propeltidium bearing ocularium; length 0.125 mm, width 0.325 mm, distance from ocular tubercle to the front of prosoma 0.1 mm. Opisthosoma with hints of weak segmentation, largely obscured by an imperfection in the matrix. Chelicerae indistinct, as are proximal articles of pedipalp. Patella of pedipalp, length 0.18 mm, with characteristic Dicranopalpus setose apophysis on mesal side, length 0.25 mm, extending about three-quarters of the way down the adjacent tibia. Tibia of pedipalp with length 0.27 mm, terminating in a further blunt, short setose apophysis. Pedipalpal tarsus widens slightly distally and ends in a single claw. Legs long and slen- der, but full lengths not preserved. Leg 2 longest, at least 8.6 mm. Measurable articles preserved in their entirety are (in mm) as follows. Leg 1: femur, 1.05; patella, 0.29; tibia, 1.02. Leg 2: femur, 2.24; patella, 0.33; tibia, 2.37. Leg 3: femur, 1.04; patella, 0.25; tibia 0.92. Ventral surface of the body not visible.

MB.A 1658 ( Figs 16 , 18-19 ) is a fairly complete specimen in dorsal view. Body oval and compact, length 1.32 mm. Prosoma with semicircular propeltidium, length 0.44 mm, dominated by prominent, heart-shaped ocularium, length 0.20, width 0.225, distance from ocular tubercle to front of prosoma 0.1 mm. Ocular tubercle bears multiple short, forward-pointing setae in a band across the dorsal region between the eyes. Dorsal surface behind propeltidium, including all opisthosomal tergites, missing. Lateral regions of body only preserved in outline. Chelicerae fairly robust, but folded un- der the body with few details. Pedipalpal trochanter short, length 0.12 mm, and quadrate. Palpal femur long, length 0.72 mm, with slight curvature and distal widening. Palpal femur setose, especially on its inferior surface. Palpal patella short, length 0.19 mm, but with prominent and characteristic Dicranopalpus mesal apophysis. Length of apophysis 0.33 mm, bearing multiple setae towards the distal end in particular and

extending almost two-thirds of the way down the length of the adjacent tibia. Palpal tibia itself elongate, length 0.51 mm, and widening distally. Palpal tarsus incomplete, but elongate, length at least 1.0, with hints of distal curvature; although terminal end is obscured. Tibia and tarsus also setose. Leg trochanters globose. Femora elongate, but incomplete in legs 2-4. Femora bear a few short setae. Femora of legs 2 and 3 preserve a proximal pseudoarticulation close to the trochanter. Leg 1 fairly complete, elongate and slender; total length at least 8.0 mm. Femur length ca. 2.0 mm. Patella not clearly preserved. Tibia length 2.60 mm. Setation on more distal podomeres indistinct, as is expected metatarsus–tarsus boundary. Ventral surface of body unknown.

Remarks. Dicranopalpus ramiger ( Koch & Berendt, 1854) is present in both Baltic and Bitterfeld amber. Both the Bitterfeld specimens described here are quite small with relatively large eye tubercles (e.g. Fig. 17 ) compared to other described fossil and Recent material in this genus. For this reason we suspect they might be juveniles. Dunlop (2006) discussed the second apophysis on the tibia – clearly preserved in MB.A 1658 ( Fig. 19 ) – which was used by Menge (1854) to define a new species. Given the poor state of preservation in the holotype of Koch and Berendt’s (1854) species, this character is regarded as unreliable and all Baltic (and now Bitterfeld) examples can probably be referred to a single taxon: D. ramiger . Note that the Bitterfeld specimen figured by Barthel and Hetzer (1982, fig. 9) from the Deutsches Bernsteinmuseum (repository number 5/2) was provisionally referred by these authors to Dicranolasma SØrensen, 1873 . This is almost certainly a lapsus since this Recent genus belongs to the dyspnoid family Dicranolasmatidae . Their figured specimen clearly bears the long patellar apophysis typical for Dicranopalpus Doleschall, 1852 (Phalangiidae) .

Figures

Figures 15-16. Dicranopalpus ramiger (Koch & Berendt, 1854) from Bitterfeld amber (Eocene: Oligocene). 15 MB.A. 1657 16 MB.A. 1658. Scale bars equal 0.5 mm (15) and 1.0 mm (16).

Figures 17-19. Dicranopalpus ramiger (Koch & Berendt, 1854) from Bitterfeld amber (Eocene: Oligocene). Camera lucida drawings of the specimens shown in 15-16. 17 MB.A. 1657 18 MB.A 1658 19 the same, detail of the long patella and short tibial apophyses (arrowed) characteristic for the genus. Scale bars equal 0.5 mm (17), 1.0 mm (18) and 0.2 mm (19).