Annazomus, 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 : 795-797

† ANNAZOMUS DE FRANCESCO MAGNUSSEN & S.P. MÜLLER GEN. NOV.

( FIGS 3–5 )

Zoobank registration: urn:lsid:zoobank.org:act:8FC98781-C14B-4E05-8E6F-A8EFD928E713

Type species: † Annazomus parvulus De Francesco Magnussen sp. nov.

Remarks

The tarsal spurs are not visible, but the specimen differs from species of Protoschizomidae by the lack of the pair of setae at the base of the anterior process and the presence of a distinct stalk at the male flagellum. It also differs from members of the Megaschizominae by having a smaller body size, the lack of eight or nine setae on its anterior process and the presence of only one pair of setae on the tergites II–VII. Therefore, it is clearly a member of subfamily Hubbardiinae . The specimen cannot be assigned to any extant genus because of its combination of characters.

Diagnosis

† Annazomus differs from all other hubbardiid genera by the following combination of characters: propeltidium with three pairs of setae; corneate eyes or eyespots absent; metapeltidium not divided; body without clavate setae; 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; male flagellum dorsoventrally flattened.

KEY TO THE FOSSIL GENERA FROM BURMESE AMBER 1. Propeltidium without single median seta …................................................................................................. 2

– Propeltidium with single median seta…........................................................................................................ 4

2. Propeltidium with three pairs of setae, corneate eyes and eyespots absent, male flagellum shape rectangular–bulbous….................................................................................................. † Annazomus parvulus

– Anterior process with a 2 + 1 setation, propeltidium with four pairs of setae, corneate eyes present …............ ............................................................................................................................................. 3 († Cretaceozomus )

3. Male flagellum shape long–bulbous …....................................................... † Cretaceozomus angustocaudatus

– Male flagellum shape bulbous–subtriangular .........................................................† Cretaceozomus robustus

4. Segment XII without posterodorsal process …................................................................................................ 5

– Segment XII with posterodorsal process …..................................................................................................... 6

5. Fixed finger of chelicerae with two small teeth between two larger outer teeth, femur IV length-to-width ratio <2.1, male flagellum shape oblong with rounded tip …......................................... † Mesozomus groehni

6. Propeltidium with four pairs of setae, male flagellum shape rhomboidal–subtriangular ….......................... ............................................................................................................................................. 7 († Groehnizomus )

– Propeltidium with three pairs of setae, male flagellum shape well rounded to subtriangular ….................... ............................................................................................................................................. 8 († Muellerizomus )

7. Metapeltidium entire, claw-to-tarsus ratio bigger than half the length of the tarsus ..................................... .................................................................................................................................… † Groehnizomus rodrigoi

– Metapeltidium divided, claw-to-tarsus ratio smaller than half the length of the tarsus ….............................. ............................................................................................................................... † Groehnizomus oculiferans

8. Corneate eyes and eyespots absent, metapeltidium divided, female flagellum with four flagellomeres …..... .................................................................................................................................. † Muellerizomus amandae

– Eyespots present, metapeltidium entire …........................................................ † Muellerizomus palicaudatus

Etymology

The genus name was chosen in honour of the first author’s grandmother Anna and is combined with the suffix -zomus, which is commonly used for schizomids. It is masculine in gender.

Comparison

† Annazomus is most similar to the new genus † Muellerizomus (described below), which has a single median seta followed by three pairs of setae on the propeltidium, whereas † Annazomus has three pairs of setae on the propeltidium. † Muellerizomus has a rounded and flat flagellum with an apical tip and a w-shaped depression on the dorsal side, but in † Annazomus the male flagellum is nearly rectangular, with a bulbous elevation on each dorsal side without any depressions. For comparison with Recent genera, see the Supporting Information ( Table S1).

Figures

Figure 3. Specimen GPIH04893, †Annazomus parvulus 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 4. Specimen GPIH04893,†Annazomusparvulus sp.nov.,holotype,details.A, metapeltidium dorsalview,photograph. B, same, interpretative drawing. C, right pedipalp in mesal 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 5. Specimen GPIH04893, †Annazomus parvulus sp. nov., holotype, details. A, flagellum in dorsal view, photograph. B, same, interpretative drawing. C, flagellum in ventral view, photograph. D, same, interpretative drawing. E, flagellum in dorsal view, three-dimensional (3D) model based on synchrotron scan. F, flagellum in ventral view, 3D model based on X-rayscan. G, flagellum in lateral view, 3D model based on X-ray-scan. See Material and methods for explanation of abbreviations. Scale bars: 0.25 mm.