Mitostoma gruberi Dunlop &amp; Mitov 2009, sp. n.
Creators: name: Dunlop, Jason
name: Mitov, Plamen
Publisher: name: Zenodo
Year: 2009
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Opiliones
Nemastomatidae
Mitostoma
Mitostoma gruberi

description: <i>Mitostoma gruberi</i> sp. n. urn:lsid:zoobank.org:act: F6F51FD0-9D10-4094-975F-3C202B48BDB9 Figs 3, 9 <b>Material.</b> MfN, MB.A. 1654. Bitterfeld amber. Probably from the site of the Goitsche Open Cast Mine near Bitterfeld, Sachsen-Anhalt, Germany; Palaeogene (Oligocene: Chattian). <b>Diagnosis.</b> Fossil <i>Mitostoma</i> with a specific form of the apophysis on the first cheliceral segment and specific form of the palpal tarsal segment. <b>Etymology.</b> In honour of Dr Jürgen Gruber (Vienna) in recognition of his extensive studies on harvestmen, and nemastomatids in particular. <b>Description.</b> MB.A. 1654 comprises a well-preserved body and pedipalps in lateral view, with a number of slightly disarticulated leg femora. Body length, 1.5 mm. Ocular tubercle distinct, eye diameter 0.20 mm. Opisthosoma with hints of segmentation and slight tuberculation on the dorsal surface towards the posterior half of the body. Chelicerae largely obscured, but dorsal part of first segment appears inflated forming an apophysis whose form is close to that of the Italian endemic <i>Mitostoma orobicum</i> (Caporiacco, 1949) (see Tedeschi and Sciaky 1997: fig. 11). Pedipalps long and slender, article lengths in mm: trochanter, 0.27; femur, 1.42; patella, 1.63; tibia, 0.80; tarsus, 0.48. Tarsus slightly swollen at its distal end. Pedipalps setose, many palpal setae, particularly towards the distal end, with rounded tips (i.e. clavate setae). Trochanters of legs oval, femora long and slender, but more distal parts of the legs equivocal. Femora with scattering of short, thorn-like spines and one femur (femur 4?) with at least three short pseudoannulations, beginning about 0.8 mm along its length. <b>Remarks.</b> This fossil can be assigned to <i>Mitostoma</i>, as opposed to <i>Nemastoma</i> C. L. Koch, 1836, on the basis of the proportions of the pedipalp articles, while the cheliceral apophysis indicates a male specimen. Whether it is juvenile or adult is less clear, but strong parallels can be drawn with the widespread European species <i>M. chrysomelas</i> (Hermann, 1804) if the fossil is juvenile, or with the Sardinian troglobitic endemic <i>M. patrizii</i> Roewer, 1953 if adult (cf. Fig. 5). Juveniles of the former and adults of the latter have small tubercles on the scutum – see especially Roewer (1953: fig. 1) and Tedeschi and Sciaky (1997: fig. 1) for <i>M. patrizii</i> – although the scutum of the fossil specimen is better developed than in comparable juveniles of <i>M. chrysomelas</i> (cf. Fig. 4). Note that an existing fossil from Baltic amber has already been assigned to <i>Mitostoma –</i> <i>M. denticulatum</i> (Koch &amp; Berendt, 1854) – transferred here from <i>Nemastoma</i> by Star&amp;eogon;ga (1976a); an interpretation followed by Dunlop (2006). On reflection, this assignment to <i>Mitostoma</i> may be incorrect and the situation is not helped by the dorsal surface of the holotype being partially broken and the apparent loss of the type material of its putative junior synonym <i>N. succineum</i> Roewer, 1939. In our revised opinion, the legs of <i>M. denticulatum</i> express lengths more consistent with modern <i>Carinostoma</i> Kratochvíl, 1958 or <i>Mediostoma</i> Kratochvíl, 1958 species. These (and other) nemastomatid genera with comparable dorsal ornament may be closer to the Baltic amber fossils. The status of <i>M. denticulatum</i> will be reassessed in a future study of Baltic amber harvestmen. Thus for the reasons outlined above we are confident that our new Bitterfeld species can be assigned to <i>Mitostoma</i> and is probably not conspecific with Koch and Berendt’s Baltic amber taxon.
description: Published as part of <i>Dunlop, Jason &amp; Mitov, Plamen, 2009, Fossil harvestmen (Arachnida, Opiliones) from Bitterfeld amber, pp. 347-375 in ZooKeys 16</i> on pages 355-356, DOI: 10.3897/zookeys.16.224, http://zenodo.org/record/576490
description: {"references": ["Caporiacco L di (1949) Un nuovo opilione e qualche altro Arachnide delle Alpi Orobie. Atti del museo civico di Storia naturale Trieste 17: 120 - 121.", "Tedeschi M, Sciaky R (1997) Towards a revision of the Italian Mitostoma. 1: Subdivision in groups and description of new species (Arachnida, Opiliones, Nemastomatidae). Revue suisse de Zoologie 104: 503 - 616.", "Hermann JF (1804) Memoire Apterologique. F. G. Levrault, Strasbourg, 144 pp.", "Roewer C-F (1953) Cavernicole Arachniden aus Sardinien. Notes Biospeologiques 8: 39 - 49.", "Koch CL, Berendt GC (1854) Die im Bernstein befindlichen Crustaceen, Myriapoden, Arachniden und Apteren der Vorwelt. Edwin Groening, Berlin, 124 pp.", "Starega W (1976 a) Opiliones Kosarze (Arachnoidea). Fauna Polski, Tom 5. Polska Akademia Nauk, Instytut Zoologii, Warszawa, 196 pp.", "Dunlop JA (2006) Baltic amber harvestman types (Arachnida: Opiliones: Eupnoi and Dyspnoi). Fossil Record 9: 167 - 182.", "Roewer C-F (1939) Opilioniden im Bernstein. Palaeobiologica 7 (1): 1 - 4.", "Kratochvil J (1958) Hohlenweberknechte Bulgariens (Palpatores - Nemastomatidae). Acta Academiae Scientiarum Cechoslovenicae Basis Brunensis 30: 523 - 576."]}