Platicrista angustata
Creators: name: Gąsiorek, Piotr
name: Blagden, Brian
name: Morek, Witold
name: Michalczyk, Łukasz
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Animalia
Tardigrada
Eutardigrada
Parachela
Hypsibiidae
Platicrista
Platicrista angustata

description: Platicrista angustata (Murray, 1905)
Diphascon angustatum; terra typica: Loch Ness, Scotland; Murray (1905b).
D. angustatum; Forth Valley, Scotland; Murray (1906b).
D. angustatum; Edinburgh, Killin, Scotland; Murray (1907).
D. angustatum; Achill Island, Belclare, Ireland; Murray (1911). Hypsibius (D.) angustatus; Dartmoor, England, Isle of Man; Morgan and King (1976).
Platicrista aff. angustata 4; Norway; Gąsiorek and Michalczyk (2020).
Material examined: 49 individuals in total (for details, see Supporting Information, Table S1).
Neotype material: Neotype and 28 specimens (slides GB.004.01– 06, GB.012.19–25, and GB.058.01–10) from Scotland, Hill of Foudland (57°23 ʹ 15″N, 2°39 ʹ 39″W; 451 m a.s.l.), lichen (Cladonia) from soil in abandoned slate quarry, 1 November 2014, Blagden coll., and Scotland, Creag Meagaidh, Lochan a’ Choire (56°57 ʹ 33″N, 4°34 ʹ 04″W; 624 m a.s.l.), moss from rock in alpine grassland, 24 March 2016, Blagden coll., are deposited in the Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków.
Comparative material: Scotland, Gartly Forest, southern boundary (57°23 ʹ 2″N, 2°42 ʹ 52″W; 390 m a.s.l.), forest, lichen (Parmelia) from stone wall, 25 April 2015, Blagden coll. (five specimens); Oxen Craig, Bennachie, Oyne, Aberdeenshire (57°17 ʹ 36″N, 2°33 ʹ 37″W; 520 m a.s.l.), heather moor, soil from rock crevice, 20 September 2015, Blagden coll. (one specimen); Drum Castle, Drumoak (57°05 ʹ 42″N, 2°20 ʹ 16″W; 114 m a.s.l.), rural vicinity, leaf litter (Quercus robur) collected from soil, 5 September 2016, Blagden coll. (three specimens); Fort Augustus, Loch Ness (57°08 ʹ 49″N, 4°40 ʹ 42″W; 20 m a.s.l.), lake shore, moss from rock, 5 November 2015, Blagden coll. (two specimens).
Redescription: Body medium-sized to very large (Table 6), elongate and slightly narrowed in its anterior part (Fig. 18A). Head blunt. Body white in smaller individuals, but brownish in the caudal part in large ones. Cuticle smooth, without pores or undulations, but with numerous irregular wrinkles intermingled with granulation in some individuals (Fig. 19). Cribriform areas not visible under PCM. Legs very short and plump; legs IV barely distinguishable from the posterior body end (Fig. 18A). Eyes absent in live animals. Buccopharyngeal apparatus of the Platicrista type. The OCA absent (Fig. 18B). Furcae of the Platicrista type, with branches pointing backwards. Pharyngeal apophyses absent; the pharyngeal tube is only slightly enlarged at its posterior end (Fig. 18B). Pharynx oval and broad, with two thin macroplacoids, the second being at least two times longer than the first (1 <2). The macroplacoid margins are serrated (Fig. 18B).
Claws of the Hypsibius type, large and robust, with thick but barely divergent accessory points, acute and slender at their tips. Primary branches of internal and anterior claws particularly massive (Fig. 20). Anterior and posterior claw bases with irregular margins under PCM (Fig. 20B); delicate indentation visible in SEM (Fig. 20E). Pseudolunulae present and well developed (Fig. 20A, B). Cuticular bars absent.
Etymology: From the Latin angustatus = narrowed, most probably referring to the tendency, as described by Murray, of the animal to taper from legs III towards the anterior end of the body. An adjective in nominative singular.
Differential diagnosis: All species of Platicrista that also lack cuticular bars on their legs are compared with P. angustata, as follows:
• P. angustata differs from P. aluna (Lisi et al., 2019) by the absence of striation of the buccal tube;
• P. angustata differs from P. carpathica sp. nov. by the absence of poorly developed indentation on all claw bases (compare Fig. 20A, B with Fig. 25B, C);
• P. angustata differs from P. horribilis by the presence of smooth pseudolunulae (compare Figs 20B and 27D);
• P. angustata differs from P. nivea sp. nov. by the presence of poorly developed indentation of claw IV bases (compare Figs 20B and 28).
description: Published as part of Gąsiorek, Piotr, Blagden, Brian, Morek, Witold & Michalczyk, Łukasz, 2024, What is a ' strong' synapomorphy? Redescriptions of Murray's type species and descriptions of new taxa challenge the systematics of Hypsibiidae (Eutardigrada: Parachela), pp. 1-63 in Zoological Journal of the Linnean Society 202 (1) on pages 26-27, DOI: 10.1093/zoolinnean/zlad151, http://zenodo.org/record/14243740