Cretaceozomus robustus, De Francesco & Magnussen, 2022, 2022

Magnussen, Ilian De Francesco, Müller, Sandro P., Hammel, Jörg U., Kotthoff, Ulrich & Harms, Danilo, 2022, Diversity of schizomids (Arachnida: Schizomida) revealed by new fossil genera and species from mid-Cretaceous Burmese amber with implications for a Gondwanan origin of the Burma Terrane, Zoological Journal of the Linnean Society 196, pp. 792-844 : 806-809

† CRETACEOZOMUS ROBUSTUS DE FRANCESCO

MAGNUSSEN SP. NOV.

( FIGS 9–11 )

Zoobank registration: urn:lsid:zoobank.org:act:5CCD94A5-55B5-44A2-929C-F441016866F9

Type material: Holotype (F i g. 9A –D), a d u l t homeomorphic ♂, collection no. GPIH05048 ; ex collection Carsten Gröhn (no. 11206).

Diagnosis

† Cretaceozomus robustus can be characterized by the following features: femur of leg IV 2.76 times longer than wide; flagellum shape semi-oval but thicker near the stalk of the flagellum.

Etymology

The specific epithet is the Latin, robustus , stout, referring to the robust body shape of the specimen. It is masculine in gender.

Description

Total length from anterior dorsal process to base of the flagellum ~ 2.86 mm.

Colour (in amber): Pedipalps dark brown reddish; prosoma dark brown to reddish; metapeltidial region lighter brown yellowish; femora dark brown-reddish, other leg segments golden-ochre; chelicerae dark brown; opisthosoma dark brown; flagellum golden brown; original colouring equivocal.

Prosoma: Length 1.25 mm; propeltidium length 1.07 mm, width 0.66 mm. Anterior process bent downwards with an apical tip, length 0.07 mm; setation: two setae next to each other followed by a single median seta. Propeltidium setation: four pairs of setae, first and second pair complete, third pair missing the left and fourth pair missing the right one owing to preservation ( Fig. 10C, D ). Corneate eyes present, clearly elevated above the surface of the propeltidium. Mesopeltidium width 0.2 mm. Metapeltidium not divided ( Fig. 10A, B ), length 0.31 mm, width 0.73 mm. Anterior sternum not entirely visible, with> 4 + 2 sternapophysial setae, length 0.31 mm, width not measurable owing to taphonomic processes. Posterior sternum covered by a syninclusion and not visible.

Chelicerae: Setation on the mesal side of chelicerae not visible, except for G6-1 and some setae of G1 and G2.

Pedipalps: Without armature except for a mesal spur on trochanter; trochanter setation: six ventral strong setae, three ventroectal, three mesal setae in tubercles; femur: longer than trochanter, setation: seven dorsal, two ectal, two+ dorsomesal, two+ mesal; patella: shorter than femur, setation: three mesal, seven ectal, four dorsomesal, four dorsoectal, three dorsal; tibia: shorter than patella, setation: five dorsomesal, four ventromesal, five ectal, three dorsoectal, nine mesal, two dorsal; tarsus: with asymmetrical tarsal spurs, spur length: 0.03 mm, setation: five ectal, four dorsoectal, three dorsal, four dorsomesal, five mesal; claw: long and straight, slightly longer than half the length of tarsus.

Legs: Right leg I aborted at the end of the coxa, left leg well preserved and complete, tarsus with six segments, leg I ~1.29 times longer than the body; anterodorsal margin of femur of leg IV produced at an angle of ~90°, leg IV 2.76 times longer than deep; leg IV 1.15 times longer than the total body length; leg formula: 1423.

Opisthosoma: Length 1.61 mm, width 0.93 mm (opisthosoma compressed owing to preservation). Tergites X–XII not elongated, tergite XII with a small posterodorsal process. Abdominal tergites setation: I– VII: Dm; VIII: Dm, Dl1, left one missing; IX: Dl1, Dl2; X: not visible; XI: Dl1, Dl2; XII: Dm, Dl1; setation pattern: 2:2:2:2:2:2:2:4:4:?:4:4. Flagellum: dorsoventrally flattened, semioval shape, broader near the stalk, slightly more slender at the posterior end, tip rounded ( Fig. 11A–D ), length 0.34 mm, width 0.33 mm; stalk length 0.14 mm; setation: Dm1 not visible; Dm4; Dl2 paired, sitting lateral; Dl3 paired with the left one aborted; Vm1; Vm2 paired; Vm3 paired; Vm5; Vl2 paired with right one aborted; between Dl2 and Dl3 four microsetae on each side. Pair Vl1 absent in this species.

Further measurements: Pedipalp: trochanter 0.39 mm; femur 0.63 mm; patella 0.56 mm; tibia 0.49 mm; tarsus 0.24 mm; claw 0.14 mm; total length 2.45 mm. Leg I: trochanter 0.23 mm; femur 0.84 mm; patella 0.94 mm; tibia 0.95 mm; metatarsus 0.35 mm; tarsus (tarsus segments) 0.39 mm (0.06 mm; 0.06 mm; 0.06 mm; 0.05 mm; 0.05 mm; 0.11 mm); total length 3.70 mm. Leg II: trochanter 0.16 mm; femur 0.73 mm; patella 0.45 mm; tibia 0.35 mm; metatarsus 0.42 mm; tarsus (tarsus segments) 0.36 mm (0.19 mm; 0.07 mm; 0.10 mm); total length 2.47 mm. Leg III: trochanter 0.20 mm; femur 0.72 mm; patella 0.30 mm; tibia 0.32mm; metatarsus 0.44 mm; tarsus (tarsus segments) 0.31 mm (0.13 mm; 0.06 mm; 0.12 mm); total length 2.29 mm. Leg IV: trochanter 0.21 mm; femur 1.16 mm; patella 0.39 mm; tibia 0.60 mm; metatarsus 0.55 mm; tarsus (tarsus segments) 0.39 mm (0.20 mm; 0.06 mm; 0.13 mm); total length 3.30 mm.

Figures

Figure 9. Specimen GPIH05048, †Cretaceozomus robustus sp. nov., holotype. A, specimen in dorsal view, photograph. B, same, interpretative drawing. C, specimen in ventral view, photograph. D, same, interpretative drawing. See Material and methods for explanation of abbreviations. Scale bars: 1 mm.

Figure 10. Specimen GPIH05048, †Cretaceozomus robustus sp. nov., holotype, details. A, metapeltidium in dorsal view, photograph. B, same, interpretative drawing. C, propeltidium in dorsal view, photograph. D, same, interpretative drawing. See Material and methods for explanation of abbreviations. Scale bars: 0.5 mm.

Figure 11. Specimen GPIH05048, †Cretaceozomus robustus sp. nov., holotype, details. A, flagellum in dorsal view, photograph. B, same, interpretative drawing. C, flagellum in ventral view, photograph. D, same, interpretative drawing. See Material and methods for explanation of abbreviations. Scale bars: 0.5 mm.