Macrobiotus maculatus Iharos, 1973

Kaczmarek, Łukasz & Michalczyk, Łukasz, 2017, A description of Macrobiotus horningi sp. nov. and redescriptions of M. maculatus comb. nov. Iharos, 1973 and M. rawsoni Horning et al., 1978 (Tardigrada: Eutardigrada: Macrobiotidae: hufelandi group), Zootaxa 4363 (1), pp. 79-100 : 86-92

Macrobiotus maculatus Iharos, 1973 comb. nov.

( Tables 2, 4, Figs 5–8 )

Macrobiotus hufelandii maculatus n. ssp. ( Iharos 1973)

Material examined ( Fig. 5 ). Two animals and one egg (neither labelled as a holotype or paratypes, which means that according to The International Code of Zoological Nomenclature ( ICZN) these should be considered as syntypes) on three slides designated as: 1) 46, Macrobiotus hufelandi maculatus Iharos, N. Guinea, Mt. Wilhelm, 1969. VIII.6., L. Balogh f. (museum accession code: HNHM Tard-280); 2) 46, Macrobiotus hufelandi maculatus Iharos, N. Guinea, Mt. Wilhelm, 1969. VIII.6., L. Balogh f. (museum accession code: HNHM Tard-286); 3) Macrobiotus hufelandi maculatus , pete., N. Guinea, Mt. Wilhelm, 1969. VIII.6., L. Balogh f. (museum accession code: HNHM Tard-287).

Type locality. 05°47'S, 145°02'E, ca. 4400–4500 m asl: New Guinea, Simbu (Chimbu) Province , near the top of the Mt. Wilhelm, above the tree line, mosses and lichens on wet rocks.

Re-description (measurements in Tables 2, 4). Animals: Body pale yellow, eyes present ( Fig. 6A ). Entire cuticle covered with conspicuous round and oval pores, not arranged in bands. Smaller pores (1.0–2.0 µm in diameter) round or slightly oval, but the larger pores (5.0–9.5 µm in diameter) always lenticular ( Fig. 6B ). Obvious granulation present on all legs ( Fig. 7D ). Bucco-pharyngeal apparatus of the Macrobiotus type, with ventral lamina and ten peribuccal lamellae ( Fig. 7A–C ). Mouth antero-ventral. The oral cavity armature of the maculatus type with only the third band of teeth visible under LM, composed of three dorsal and three ventral teeth in the shape of transverse ridges ( Fig. 7B–C ). Buccal tube with a single anterior bend and slightly thickened walls posterior to the stylet support insertion point. Pharyngeal bulb spherical with triangular apophyses, two rod-shaped macroplacoids and a thin microplacoid. Macroplacoid length configuration 2<1. The first macroplacoid with a central constriction. The second macroplacoid without constrictions, but with latero-terminal globular projections ( Fig. 7A ). Claws of the hufelandi type, stout ( Fig. 7D ). Primary branches with distinct accessory points. Lunules on all legs smooth. Thin paired bars under claws I–III present. Other cuticular thickenings on legs absent.

Eggs: Spherical, ornamented and laid freely ( Fig. 8A ), with the chorion surface of the maculatus type (porous; Fig. 8B–C ). Pores (pits) large (0.8–1.5 µm in diameter) and oval, up to 20 arranged in peribasal rings, with occasional smaller interbasal pores. Process trunks concave, very wide at the base, narrowed immediately above the base and then almost uniformly thin to the top, terminated with a small disc ( Fig. 8D ). Discs almost flat (from slightly concave to slightly convex) and with smooth edges.

Original measurements according to Iharos (1973): Body length 360–410 µm; cuticular pores 6.0×1.2 µm; pharyngeal bulb 43.0×36.0 µm; eggs with and without processes 100.0×80.0 µm and 65.0×85.0 µm, respectively; processes height 9.0 µm; 30–32 process on egg circumference.

Etymology. Not explained in the original description, but possibly refers to the conspicuous cuticular pores that may resemble spots ( maculatus is a derivative of the Latin maculosum = spotted).

Type depositories. Syntypes are preserved at the Hungarian Natural History Museum , Department of Zoology, Baross 13, Budapest, Hungary.

Differential diagnosis. Macrobiotus maculatus comb. nov. is characterised by eggs of the maculatus type (see, Kaczmarek & Michalczyk 2017 for details), and is most similar to the following four species, but can be distinguished from:

M. biserovi Bertolani et al., 1996 , reported from the type locality in Italy, by: a different oral cavity armature type ( maculatus type in M. maculatus vs. hufelandi type in M. biserovi ), presence of granulation on legs IV (cuticular granulation in M. biserovi absent), the absence of teeth on lunules IV, a higher number of processes on the egg circumference (ca. 31 in M. maculatus vs. ca. 24 in M. biserovi ), a different shape of terminal discs of egg processes (round in M. maculatus vs. pentagonal in M. biserovi ), terminal discs narrower than the base of egg processes (discs and bases of a similar diameter in M. biserovi ), and narrower bases of egg processes (5.9–6.7 µm in M. maculatus vs. 8.3–9.2 µm in M. biserovi ).

M. denticulatus Dastych, 2002 , recorded from type locality in the Kerguelen Islands (sub-Antarctic), by: a different oral cavity armature type ( maculatus type in M. maculatus vs. patagonicus type in M. denticulatus ), a higher pt of the stylet support insertion point (77.6–79.2 in M. maculatus vs. 71.2–76.7 in M. denticulatus ), the absence of teeth on terminal discs of egg processes, a lower process base/height ratio (71–83% in M. maculatus vs. 95–99% in M. denticulatus ), and narrower bases of egg processes (5.9–6.7 µm in new species vs. 8.0–12.0 µm in M. denticulatus ).

M. macrocalix Bertolani & Rebecchi, 1993 , recorded from several localities in Europe and the Seychelles (Bertolani & Rebecchi 1996, Vargha 1998, Kaczmarek & Michalczyk 2002, Pilato et al. 2002, Jönsson 2007, Guil 2008), by: a different oral cavity armature type ( maculatus type in M. maculatus vs. hufelandi type in M. macrocalix ), a higher number of processes on the egg circumference (ca. 31 in new species vs. ca. 26 in M. macrocalix ), a lower process base/height ratio (71–83% in M. maculatus vs. 101–112% in M. macrocalix ), narrower bases of egg processes (5.9–6.7 µm in M. maculatus vs. 8.6–12.1 µm in M. denticulatus ) and smaller diameter of terminal discs on the egg processes (2.5–3.6 µm in M. maculatus vs. 7.2–10.9 µm in M. macrocalix ).

M. ramoli Dastych, 2005 , reported from the type locality in Austria, by: a different oral cavity armature type ( maculatus type in M. maculatus vs. patagonicus type in M. ramoli ), a lower number of processes on the egg circumference (ca. 31 in M. maculatus vs. 35–41 in M. ramoli ), the absence of projections on terminal discs of the egg processes, and a lower process base/height ratio (71–83% in M. maculatus vs. 100–111% in M. ramoli ).

Figures

FIGURE 5. Macrobiotus maculatus Iharos, 1973 comb. nov.—slides constituting the type series.

FIGURE 6. Macrobiotus maculatus Iharos, 1973 comb. nov. A—habitus (syntype); B—dorsal cuticle with pores (white arrowhead indicates a large pore whereas black arrowhead shows a small pore; synype).Scale bars in µm.

FIGURE7. Macrobiotusmaculatus Iharos, 1973 comb. nov. A—buccalapparatus (syntype); B–C—oral cavity armature(Bdorsal teeth, C—ventral teeth; arrows indicates the third band of teeth; syntype); D—claws I (patch of granulation is outlined with a dashed curve; syntype). Scale bars in µm.

FIGURE8. Macrobiotus maculatus Iharos, 1973comb.nov. A—egg; B–C—chorionic pores; D—egg processes (midsection). Scale bars in µm.