Tardigrada and Rotifera from moss microhabitats on a disappearing Ugandan glacier, with the description of a new species of water bear Author Zawierucha, Krzysztof Author Gąsiorek, Piotr Author Buda, Jakub Author Uetake, Jun Author Janko, Karel Author Fontaneto, Diego text Zootaxa 2018 2018-03-09 4392 2 311 328 journal article 30561 10.11646/zootaxa.4392.2.5 6102dc82-f472-4c39-9e7f-f9b05956cec4 1175-5326 1195435 7FD2CE64-66AB-4555-B8BF-D97A8496D2E0 Adropion afroglacialis sp. nov. Zawierucha, Gąsiorek & Buda Material. Holotype (slide U/8) and paratypes including 35 individuals, one simplex and two exuviae (slides numbers: U/2–9, U/12–13, U/15–20) are deposited in the Department of Animal Taxonomy and Ecology at Adam Mickiewicz University, Poznań, Poland . Five paratypes (slides UG.007.01 [U/1] and UG.007.02[U/14], and three paratypes mounted on a SEM stub) are deposited in the Institute of Zoology and Biomedical Research, Jagiellonian University, Kraków, Poland . Type locality. Mount Stanley , Rwenzori Mountains ( 0°22'31''N , 29°52'40''E ; 4790 m asl ), Uganda . Etymology. The name afroglacialis means “occurring on an African glacier” and refers to the ecosystem where the new species was found. Description. Body colourless or whitish in vivo as well as in slide mounts ( Fig. 2A ). Cuticle covered with faint irregular granulation (granules forming small dots), more visible on dorsal side and legs, sometimes poorly visible ( Figs. 2B–E ), for details see Remarks. Eyes absent in mounted specimens ( Figs. 2A , 3A–B ). Oral cavity armature not visible under PCM ( Figs. 3A–B ). Stylet furcae of the Hypsibius - type , unmodified ( Figs. 3A–B ). Drop-like thickening absent at the junction between the buccal and the pharyngeal tube ( Figs. 2A , 3A–B ). Annulation of the pharyngeal tube clearly visible in DIC ( Fig. 3A ) as a single narrow annuli ( Fig. 3D ). Pharynx with three double rows of macroplacoids, microplacoid and septulum ( Figs. 3A–C ). The apophyses clearly separated from the 1 st macroplacoids . All macroplacoids clearly separated. Macroplacoid length sequence 2<1<3 (however in five specimens out of twenty four the first macroplacoid is shorter than the second—the difference ranges are 0.1–0.2 µm); macroplacoids bar-shaped, arranged in parallel. All macroplacoids without constrictions ( Figs. 3A–C ). Microplacoids in the form of small round granules. Elongated septulum present ( Figs. 3A–C ). Claws of the Hypsibius type , with widened bases and with obvious accessory points on the primary branches ( Figs. 4A–E ). On the primary branch, at the border between accessory points and primary claw branch, a thick line is visible along entire branch length. Internal and anterior claws usually with two septa dividing the claw into the basal portion, the secondary branch, and the primary branch ( Fig. 4C ). Claws with poorly visible pseudolunulae ( Figs. 4A–D , arrowheads). Bases of all claws smooth. Cuticular bars absent. FIGURE 2. Adropion afroglacialis sp. nov. : A—habitus, holotype, dorso-ventral projection (PCM), B—granulation on the dorsal side in the middle section of holotype indicated by arrows (PCM), C—granulation on the dorsal side of paratype (PCM), D—granulation on the dorsal side in the anterior section of holotype indicated by arrows (DIC), E—granulation on the III leg of paratype (PCM). All scale bars in micrometres. FIGURE 3. Adropion afroglacialis sp. nov. : A—bucco-pharyngeal apparatus, holotype (PCM), B—bucco-pharyngeal apparatus, holotype (DIC), C—pharyngeal structures, holotype (PCM), D—annulation of the pharyngeal tube, paratype (SEM). All scale bars in micrometres. FIGURE 4. Adropion afroglacialis sp. nov. : A—claws I, paratype (PCM), B—claws II, paratype (SEM), C—claws IV, paratype (PCM), D—claws IV, paratype (SEM), E—claws IV and cloaca, paratype (SEM). Arrowheads indicate poorly visible pseudolunulae. All scale bars in micrometres. TABLE 1. Measurements [in µm] of selected morphological structures of individuals of Adropion afroglacialis sp. nov. mounted in Hoyer’s medium (N—number of specimens/structures measured, RANGE refers to the smallest and the largest structure among all measured specimens; SD—standard deviation).

CHARACTER	N	RANGE		MEAN		SD	Holotype
µm	pt	µm	pt	µm	pt	µm	pt
Body length	17	144	–	250	738	–	997	192	871	34	96	222	997
Bucco-pharyngeal tube
Buccal tube length	22	19.1	–	26.8	–	22.0	–	2.2	–	22.3	–
Pharyngeal tube length	18	26.1	–	41.6	129.2	–	184.1	34.0	156.1	4.4	15.0	29.3	131.4
Buccopharyngeal tube length	19	46.3	–	65.4	229.2	–	284.1	52.8	256.1	14.0	15.0	51.6	231.4
Bucco/pharyngeal tube length ratio	18	54%	–	77%	–	65%	–	6%	–	76%	–
Stylet support insertion point	19	11.6	–	14.9	54.5	–	63.5	13.0	59.4	1.1	2.7	12.7	57.0
Buccal tube external width	22	1.6	–	2.6	7.8	–	10.2	2.0	9.2	0.2	0.6	2.1	9.4
Buccal tube internal width	22	0.8	–	1.4	4.0	–	5.9	1.1	4.9	0.2	0.7	0.9	4.0
Placoid lengths
Macroplacoid 1	24	1.9	–	3.2	9.4	–	12.9	2.5	11.6	0.4	0.9	2.6	11.7
Macroplacoid 2	24	1.9	–	3.0	9.5	–	12.7	2.5	11.3	0.4	1.0	2.5	11.2
Macroplacoid 3	24	2.1	–	4.1	10.5	–	17.2	3.2	14.6	0.6	1.9	3.2	14.3
Microplacoid	22	0.6	–	1.3	2.5	–	5.4	0.9	3.9	0.2	0.8	0.9	4.0
Septulum	23	1.6	–	2.7	7.5	–	13.1	2.1	9.3	0.3	1.5	1.8	8.1
Macroplacoid row	24	7.3	–	11.4	36.5	–	50.0	9.5	43.3	1.5	4.0	9.4	42.2
Placoid row	24	10.1	–	15.1	50.5	–	65.4	12.6	57.9	1.6	4.0	12.7	57.0
Claw 1 lengths
External base	14	2.7	–	4.4	13.4	–	17.9	3.5	15.8	0.6	1.5	4.0	17.9
External primary branch	15	4.8	–	6.8	20.1	–	30.4	5.6	25.6	0.6	2.4	5.8	26.0
External secondary branch	15	3.1	–	4.7	15.8	–	20.6	4.0	18.1	0.6	1.4	4.1	18.4
Internal base	9	2.2	–	3.4	11.2	–	15.2	2.9	12.7	0.4	1.2	3.4	15.2
Internal primary branch	9	2.3	–	5.3	11.4	–	20.6	4.0	17.8	0.9	3.0	4.6	20.6
Internal secondary branch	10	2.3	–	4.1	11.6	–	19.3	3.4	14.8	0.6	2.8	4.1	18.4
Claw 2 lengths
External base	15	2.6	–	5.4	12.7	–	20.1	3.7	16.7	0.8	2.6	4.0	17.9
External primary branch	15	5.2	–	7.6	22.8	–	34.8	6.4	28.9	0.8	3.4	7.3	32.7
External secondary branch	15	3.0	–	5.3	15.0	–	22.5	4.3	19.2	0.8	2.3	4.5	20.2
Internal base	13	2.4	–	4.3	11.9	–	18.1	3.2	14.0	0.7	2.2	3.4	15.2
Internal primary branch	10	3.7	–	6.3	18.9	–	24.9	4.9	21.3	0.8	2.3	5.5	24.7
Internal secondary branch	14	2.6	–	5.1	13.0	–	21.4	3.9	17.2	0.7	2.8	4.3	19.3
Claw 3 lengths
External base	19	2.4	–	5.1	11.8	–	21.7	3.8	17.2	0.8	2.9	4.1	18.4
External primary branch	20	4.5	–	8.0	22.3	–	37.3	6.3	29.0	1.0	3.3	6.6	29.6
External secondary branch	19	3.0	–	5.5	15.3	–	22.6	4.1	18.9	0.7	1.9	4.3	19.3

......continued on the next page Remarks and differential diagnosis. Granulation is poorly visible or not visible on some individuals, completely undistinguishable in SEM. Granulation is invisible in SEM, but is visible in both PCM and DIC, indicating that it may be comprised of depressions (fossae) covered with cuticle. On the holotype, granulation is visible only in some areas on the dorsal side. Thus, observation of cuticle should be done carefully. In five specimens, the first macroplacoid is shorter than the second; the difference ranges between 0.1–0.2 µm. Currently, the genus Adropion consist of twenty species (Degma et al . 2009–2017 ), but from a molecular point of view the genus appears polyphyletic and potentially with cryptic diversity ( Bertolani et al . 2014 ). It is first report of the genus Adropion from Uganda ( McInnes et al . 2017 ). TABLE 1. (Continued)

CHARACTER	N	RANGE		MEAN		SD	Holotype
µm	pt	µm	pt	µm	pt	µm	pt
Internal base	14	2.3	–	4.4	11.3	–	17.2	3.3	14.5	0.6	1.8	3.2	14.3
Internal primary branch	13	3.7	–	6.3	16.5	–	25.4	4.6	20.8	0.9	2.5	?	?
Internal secondary branch	16	3.0	–	4.8	14.2	–	19.0	3.9	17.1	0.5	1.4	4.2	18.8
Claw 4 lengths
Anterior base	16	2.4	–	4.5	12.2	–	17.2	3.3	15.0	0.7	1.7	3.7	16.6
Anterior primary branch	17	3.0	–	6.5	15.2	–	25.7	4.8	21.4	0.9	2.7	5.7	25.6
Anterior secondary branch	17	2.6	–	5.7	12.9	–	25.0	3.9	17.3	0.9	3.2	4.3	19.3
Posterior base	17	2.6	–	5.4	13.0	–	20.1	3.6	16.3	0.8	2.2	4.1	18.4
Posterior primary branch	17	3.3	–	9.0	16.8	–	39.2	6.9	31.0	1.8	6.4	8.1	36.3
Posterior secondary branch	17	3.0	–	5.9	13.0	–	29.9	4.5	20.5	0.9	4.3	4.8	21.5

Apart from the peculiar granulation on cuticle, by having three macroplacoids, microplacoid and septulum in the pharynx, the new species is most similar to the following Adropion species: A. gordonense (Pilato, Claxton & Horning, 1991) , A. greveni ( Dastych, 1984 ) , A. linzhiensis ( Li, 2007 ) , and A. onorei (Pilato, Binda, Napolitano & Moncada, 2002) , but it specifically differs from: - A. gordonense by clearly smaller pharyngeal apophyses (compare: Fig. 1b in Pilato et al . 1991), and absence of thickened bars under internal claws I–III. - A. greveni by absence of long bars under internal claws I–III, the absence of spines under the claws, and much shorter macroplacoid row and all macroplacoids (macroplacoid row length 7.3–11.4 µm in A. afroglacialis sp. nov. vs 18–24 µm in A. greveni ). - A. linzhiensis by having a less elongated body (compare: Figs. 6 –7 in Li (2007)) , a different macroplacoid length sequence (2<1< 3 in the new species vs. 1<2< 3 in A. linzhiensis ), relatively shorter macroplacoid row ( 36.5–50 % in A. afroglacialis sp. nov. vs 50–57.1 % in A. linzhiensis ), and relatively shorter claws I–IV (external claw secondary branches 15.0–22.6 %, internal + anterior claw primary branches 11.4–25.7 %, and internal claw secondary branches 11.6–21.4 % in A. afroglacialis sp. nov. vs 25.0–37.5 %, 25.0–37.5 %, and 22.6–37.3 % in A. linzhiensis , respectively). - A. onorei by absence of bars under internal claws I–III, and absence of spines under posterior claws IV, the stylet supports inserted more anteriorly on the buccal tube ( 54.5–63.5 % in A. afroglacialis sp. nov. vs 64.2– 65.3 % in A. onorei ), much shorter macroplacoid row (7.3–11.4 µm [ 36.5–50 %] in A. afroglacialis sp. nov. vs 14.9–17.7 µm [ 78.8–84.3 %] in A. onorei ).