Groehnizomus, 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 : 818-822

† GROEHNIZOMUS RODRIGOI S.P. MÜLLER SP. NOV.

( FIGS 20–23 )

Zoobank registration: urn:lsid:zoobank.org:act:97BC6CF7-BF6A-48C1-968E-069699D99D4A

Ty p e m a t e r i a l: Holotype (Fig. 2 0A–D), adult homeomorphic ♂, collection no. GPIH04891 , ex collection Patrick Müller (no. BUB83 ) .

Diagnosis

† Groehnizomus rodrigoi differs from † G. oculiferans by the state of the metapeltidium, which is divided in † G. oculiferans and entire in † G. rodrigoi . Although the state of the metapeltidium is no longer considered diagnostic at genus level ( Lawrence, 1969), this character still shows great consistency within a given genus. Therefore, we consider † G. rodrigoi to be distinct from † G. oculiferans .

Etymology

The genus name is a patronym for Rodrigo MonjarazRuedas from the Universidad Nacional Autónoma de México and honours his outstanding contribution to modern schizomid taxonomy and phylogenetics. It is masculine in gender.

Description

Total length from anterior margin of the propeltidium to base of flagellum 2.72 mm.

C o l o u r: L i g h t–d a r k b r o w n, o r i g i n a l c o l o u r i n g equivocal.

Prosoma: Length 1.08 mm; propeltidium length 0.87 mm, width 0.38 mm. Anterior process with a single seta followed by a pair of setae. Further setation of propeltidium a single seta followed by four pairs of setae, all four pairs aborted ( Fig. 21C, D ). Corneate eyes present, clearly elevated above the surface of the propeltidium. Mesopeltidia length> 0.13 mm, width equivocal. Metapeltidium not divided ( Fig. 21A, B ), length 0.58 mm, width 0.28 mm. Anterior sternum with 12 + 2 sternapophysial setae. Posterior sternum with 5+ setae.

Pedipalps: Stout and clearly shorter than the body length, without armature ( Fig. 22A, B ), mesal spur not visible; trochanter not produced anteriorly, setation: six strong, long ventral, six+ small ventromesal–ventroectal; femur setation: six+ dorsal, one dorsomesal, three ventral; patella slightly longer than femur, setation: three dorsal, three dorsomesal, one dorsoectal, two ventroectal, two ventral; tibia shorter than patella, setation: three+ dorsal, four dorsoectal, nine ventroectal–ventromesal, mesal setation equivocal; tarsus about two-thirds length of tibia, setation: three+ dorsoectal, three mesal, four ventromesal, dorsal setation equivocal; tarsal spurs equivocal; claw slightly shorter than half the length of tarsus.

Chelicerae: Setation of the mesal side of chelicerae not visible, except for G6-1.

822 I. DE FRANCESCO MAGNUSSEN ET AL.

Legs: Anterodorsal margin of femur of leg IV produced at an angle of ~90°; leg IV 1.37 times longer than the body, femur of leg IV slender, 3.27 times longer than deep; leg formula: 1423.

Opisthosoma: Length 1.63 mm, width 0.60 mm; tergites X–XII not elongated. Abdominal tergites setation: I: Dm, five microsetae; II: Dm; III–XII: disrupted; setation pattern: 2 + 5:2:?:?:?:?:?:?:?:?:?:?. Flagellum: dorsoventrally flattened, rounded to subrhomboidal ( Fig. 23A–D ), length 0.30 mm, width 0.24 mm; stalk length 0.07; setation: Dm1 (lost), Dl2 paired, Dm4 (lost), Dl3 paired, Vm1, Vm2 paired, Vm3 paired, Vl1 paired, Vm5, Vl2 paired.

Further measurements: Pedipalp: trochanter 0.36 mm; femur 0.49 mm; patella 0.55 mm; tibia 0.36 mm; tarsus 0.21 mm; total length 1.97 mm. Leg I: trochanter 0.27 mm; femur 1.20 mm; patella 1.52 mm; tibia 1.04 mm; metatarsus 0.34 mm; tarsus 0.41 mm; total length 4.78 mm. Leg II: trochanter 0.17 mm; femur 0.69 mm; patella 0.38 mm; tibia 0.52 mm; metatarsus 0.47 mm; tarsus 0.37 mm; total length 2.60 mm. Leg III: trochanter 0.16 mm; femur 0.66 mm; patella 0.26 mm; tibia 0.38 mm; metatarsus 0.43 mm; tarsus 0.39 mm; total length 2.28mm. Leg IV: trochanter 0.24 mm; femur 1.21 mm; patella 0.49 mm; tibia 0.72 mm; metatarsus 0.65 mm; tarsus 0.41 mm; total length 3.72 mm.

Figures

Figure 20. Specimen GPIH04891, †Groehnizomus rodrigoi, 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 21. Specimen GPIH04891, †Groehnizomus rodrigoi 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 22. Specimen GPIH04891, †Groehnizomus rodrigoi sp. nov., holotype, details. A, left pedipalp in ectal view, photograph.B, same, interpretative drawing. See Material and methods for explanation of abbreviations. Scale bars: 0.5mm.

Figure 23. Specimen GPIH04891, †Groehnizomus rodrigoi, 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.