Diphascon angustatum, Murray, 1905

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), Zoological Journal of the Linnean Society 202 (1), pp. 1-63 : 26-28

publication ID	https://doi.org/ 10.1093/zoolinnean/zlad151
publication LSID	lsid:zoobank.org:pub:044A402-2A0F-4135-9410-7DE081CB11C4Corresponding
persistent identifier	https://treatment.plazi.org/id/03AF87C4-A620-FFA9-AE6B-6B64FB4A8DBA
treatment provided by	Plazi
scientific name	Diphascon angustatum
status

Treatment

D. angustatum View in CoL ; Edinburgh, Killin, Scotland; Murray (1907) .

D. angustatum View in CoL ; Achill Island, Belclare, Ireland; Murray (1911). Hypsibius (D.) angustatus View in CoL ; Dartmoor, England, Isle of Man; Morgan and King (1976).

Platicrista aff. angustata View in CoL 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 GoogleMaps .

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) GoogleMaps ; 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) GoogleMaps ; 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) GoogleMaps ; 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) GoogleMaps .

Redescription: Body medium-sized to very large ( Table 6), elongate and slightly narrowed in its anterior part ( Fig. 18A View Figure 18 ). 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 View Figure 19 ). Cribriform areas not visible under PCM. Legs very short and plump; legs IV barely distinguishable from the posterior body end ( Fig. 18A View Figure 18 ). Eyes absent in live animals. Buccopharyngeal apparatus of the Platicrista type. The OCA absent ( Fig. 18B View Figure 18 ). 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 View Figure 18 ). 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 View Figure 18 ).

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 View Figure 20 ). Anterior and posterior claw bases with irregular margins under PCM ( Fig. 20B View Figure 20 ); delicate indentation visible in SEM ( Fig. 20E View Figure 20 ). Pseudolunulae present and well developed ( Fig. 20A, B View Figure 20 ). 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 View in CoL differs from P. aluna ( Lisi et al., 2019) by the absence of striation of the buccal tube;

• P. angustata View in CoL differs from P. carpathica sp. nov. by the absence of poorly developed indentation on all claw bases (compare Fig. 20A, B View Figure 20 with Fig. 25B, C View Figure 25 );

• P. angustata differs from P. horribilis by the presence of smooth pseudolunulae (compare Figs 20B View Figure 20 and 27D View Figure 27 );

• P. angustata differs from P. nivea sp. nov. by the presence of poorly developed indentation of claw IV bases (compare Figs 20B View Figure 20 and 28 View Figure 28 ).

Platicrista borneensis Gąsiorek & Michalczyk sp. nov. ZooBank registration: urn:lsid:zoobank.org:act:08931145-78C1-439F-85DD-2A48C3CA516B

Material examined: 10 individuals in total (for details, see Supporting Information, Table S1).

Type material: Holotype (slide MY.100.01) and eight paratypes (slides MY.090.01, MY.091.02, MY.100.01, and MY.826.04) from Malaysia, Borneo , Sarawak, Gunung Mulu , The Main Trail (4°02 ʹ N, 114°48 ʹ E; ~ 60 m a.s.l.), moss from tree trunk in a primary rainforest, 27 July 2016, Gąsiorek coll., and Malaysia, Borneo, Sarawak, Bako Peninsula (1°43″16‘N, 110°27 ʹ 39″E; 107 m a.s.l.), moss from soil and tree trunk in a primary rainforest, 5 August 2017, Gąsiorek & Oczkowski coll., are deposited in the Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków. GoogleMaps

Description: Body white and elongate ( Table 7), with blunt cephalic part ( Fig.21A, B View Figure 21 ). Cuticle smooth, without pores, wrinkling or granulation. Cribriform areas not visible under PCM. Legs short, and even legs IV poorly delimited from the caudal body end. Eyes absent in unmounted animals. Buccopharyngeal apparatus of the Platicrista type ( Fig. 21B View Figure 21 ): OCA not visible under PCM, annulated pharyngeal tube shorter than rigid buccal tube, both being moderately wide; stylet supports embedded anteriorly on the buccal tube; furcae of the Platicrista type (cochlear); pharyngeal apophyses absent; pharynx oval, with two bar-like macroplacoids: the first distinctly shorter than the second (1 <2).

Claws of the Hypsibius type, delicate and slender ( Fig. 21C View Figure 21 ). Accessory points not discernible on the primary branches of the external claws, but identifiable on the primary branches of the internal claws and only slightly separated from them. Septa between claw parts absent. Pseudolunulae absent. Median and posterior cuticular bars present ( Fig. 21A, C View Figure 21 ).

Etymology: The name signifies the terra typica. An adjective in nominative singular.

Differential diagnosis: There are three congeneric species with cuticular bars on their legs: Platicrista brunsoni Miller and J.D. Miller, 2021 , Platicrista cheleusis Kathman, 1990 , and Platicrista ramsayi Marley, 2006 . Platicrista borneensis can be differentiated from them based on: • P. brunsoni , the presence of median bars (present in P. borneensis vs. absent in P. brunsoni ), the presence of polygonal sculpturing on the dorsum (absent in P. borneensis vs. present in P. brunsoni ), and the presence of indentation on the base of claws IV (absent in P. borneensis vs. present in P. brunsoni );

• P. cheleusis , the presence of median bars (present in P. borneensis vs. absent in P. cheleusis ), and the presence of polygonal sculpturing on the dorsum (absent in P. borneensis vs. present in P. cheleusis );

• P. ramsayi , the presence of median bars (present in P. borneensis vs. absent in P. ramsayi ).