Cretaceozomus, DE FRANCESCO MAGNUSSEN &, 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 : 801-802

† CRETACEOZOMUS DE FRANCESCO MAGNUSSEN &

S.P. MÜLLER GEN. NOV.

( FIGS 6–11 )

Zoobank registration: urn:lsid:zoobank.org:act:36AEDFB3-9F9B-4A46-9330-C272B75F352C

Type species: † Cretaceozomus robustus De Francesco Magnussen sp. nov.

Remarks

Specimens of this genus show asymmetrical tarsal spurs (equivocal in † Cretaceozomus angustocaudatus ) and also differ from species of Protoschizomidae by lack of the pair of setae at the base of the anterior process and by the presence of a distinct stalk at the male flagellum. They also differ from members of the Megaschizominae by having a smaller body size, lack of eight or nine setae on their anterior process and the presence of only one pair of setae on the tergites II– VII. Therefore, they are clearly members of subfamily Hubbardiinae . The specimens cannot be assigned to any extant genus because of their combination of characters and the particular setation of the male flagellum.

Diagnosis

† Cretaceozomus differs from all other hubbardiid genera by the following combination of characters: anterior process with two setae next to each other followed by a single median seta (2 + 1), propeltidium with four pairs of setae; corneate eyes present; metapeltidium not divided; body without clavate setae; pedipalp trochanter with a mesal spur; anterodorsal margin of femur of leg IV produced at an angle of ~90°; tergite II with one pair of setae; tergites X–XII not elongated; tergite XII with posterodorsal process (equivocal in † Cretaceozomus angustocaudatus ); male flagellum dorsoventrally flattened and without the pair Vl1.

Note

Although the presence of a posterodorsal process in † Cretaceozomus angustocaudatus cannot be verified, the species can still be discriminated genuinely from any other Recent fauna (see Supporting Information, Table S1).

Etymology

The genus name stems from the Cretaceous Era, which is the geological period of the formation of

Burmese amber, and the suffix -zomus, the last letters of Schizomus . It is masculine in gender.

Comparisons

† Cretaceozomus is similar to Zomus Reddell & Cokendolpher, 1995 , an extant genus widespread in SoutheastAsiaandOceania( Reddell&Cokendolpher,1995; Harvey, 2001b; Manzanilla, 2010). A secure assignment of † Cretaceozomus to the genus Zomus is not possible owing to the fact that males of Zomus are still unknown, and all specimens of † Cretaceozomus are males. Therefore, important diagnostic characters (e.g. spermathecae, male flagellum shape) cannot be compared. Until additional material becomes available, it seems premature to merge the genera Zomus and † Cretaceozomus . † Cretaceozomus is also similar to Ovozomus Harvey, 2001b found from the Comoros to the Cook Islands, but Ovozomus has eye spots, whereas † Cretaceozomus bears corneate eyes. The male flagellum is spade shaped in Ovozomus and bulbous in † Cretaceozomus . Also, the body size range of Ovozomus is larger at 4.00– 5.51 mm compared with 2.86–3.00 mm in † Cretaceozomus . † Cretaceozomus shares characters with † Annazomus , which has three pairs of setae on the propeltidium and lacks eyes (four pairs of setae and eyes present in † Cretaceozomus ). In † Annazomus , the male flagellum shape is nearly rectangular with a bulbous elevation, whereas the flagellum of † Cretaceozomus has a semi-oval shape. † Cretaceozomus shares characters with † Muellerizomus , which has three pairs of setae on the propeltidium and eye spots (four pairs and corneate eyes in † Cretaceozomus ). Both genera differ also in flagellum shape. † Cretaceozomus shares characters with † Muellerizomus , but the latter has a single median seta followed by three pairs of setae on the propeltidium (four pairs in † Cretaceozomus ). † Muellerizomus also lacks eyes and differs in flagellum shape. For comparison with Recent genera, see the Supporting Information ( Table S1).

Figures

Figure 6. Specimen GPIH04896, †Cretaceozomus angustocaudatus 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 7. Specimen GPIH04896, †Cretaceozomus angustocaudatus sp. nov., holotype, details. A, prosoma in dorsal view, photograph. B, same, interpretative drawing. C, right pedipalp in ectal view, photograph. D, same, interpretative drawing. See Material and methods for explanation of abbreviations. Scale bars: 0.5 mm.

Figure 8. Specimen GPIH04896, †Cretaceozomus angustocaudatus sp. nov., holotype, details. A, metapeltidum 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: 0.25 mm (A, B); 0.5 mm (C, D).

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.