Integrative description of two new species of the genus Mesobiotus (Eutardigrada, Macrobiotoidea) from Russia, with an updated phylogeny of the genus Author Tumanov, Denis V. 49E22A70-C27B-485B-941E-577666EE65F9 Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, 199034, Universitetskaya nab. 7 / 9, Saint Petersburg, Russia. & Marine Research Laboratory, Zoological Institute of the Russian Academy of Sciences, 199034, Universitetskaja nab. 1, Saint Petersburg, Russia. d.tumanov@spbu.ru Author Androsova, Evgenia D. 73698C49-9E5B-48F0-A271-03886446FF08 Soil Science & Soil Ecology Department, Institute of Earth Sciences, Saint Petersburg State University, 16 Linija, 29, Saint Petersburg, 199178, Russia. eugenia.androsova@gmail.com Author Gavrilenko, Marina D. 63202CD2-E90E-482C-B2DF-92A354821CDE Department of Genetics and Biotechnology, Faculty of Biology, Saint Petersburg State University, 199034, Universitetskaya nab. 7 / 9, Saint Petersburg, Russia. md.gavrilenko7@gmail.com Author Kalimullin, Aidar A. 641F4F4E-D6FD-423B-B683-04ABDB4628F3 Department of Invertebrate Zoology, Faculty of Biology, Far Eastern Federal University, 10 Ajax Bay, Russky Island, Vladivostok, 690922, Russia. kalimullin.aa@students.dvfu.ru text European Journal of Taxonomy 2024 2024-07-30 947 1 20 52 https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2619/12017 journal article 300355 10.5852/ejt.2024.947.2619 c86124cd-85bf-45a0-93c2-df674e3762a5 2118-9773 13134040 5B9DA044-2842-456C-8339-2D097A24A662

Table 2. Summary of morphometric data for Mesobiotus efa sp. nov. Measurements are given in µm, pt values in % (the pt index is the percentage ratio between the length of a structure and the length of the buccal tube).

CHARACTER	N			RANGE				MEAN		SD		Holotype
			µm			pt		µm	pt	µm	pt	µm	pt
Body length	17	238	–	430	759	–	1048	321	856	51	72	430	940
Buccopharyngeal tube
Buccal tube length	21	29.7	–	45.8		–		38.1	–	4.5	–	45.8	–
Stylet support insertion point	21	22.6	–	35.3	74.0	–	78.8	29.3	77.0	3.5	1.0	35.3	77.2
Buccal tube external width	21	4.1	–	8.6	12.1	–	19.6	5.6	14.6	1.0	1.5	6.7	14.7
Buccal tube internal width	21	3.1	–	7.6	8.4	–	17.2	4.2	10.9	1.0	1.6	5.0	10.9
Ventral lamina length	19	17.3	–	27.2	56.6	–	61.4	22.4	59.5	2.9	1.4	27.2	59.5
Placoid lengths
Macroplacoid 1	21	2.3	–	6.5	7.7	–	15.6	4.7	12.1	1.1	1.9	5.9	12.9
Macroplacoid 2	21	2.4	–	5.1	7.9	–	12.6	3.8	9.9	0.7	1.1	4.7	10.3
Macroplacoid 3	21	2.7	–	6.5	9.2	–	14.2	4.6	11.9	1.0	1.4	6.5	14.1
Microplacoid	21	1.6	–	4.9	5.5	–	11.2	3.6	9.4	0.8	1.6	4.8	10.5
Macroplacoid row	21	9.3	–	18.6	31.3	–	45.3	14.6	38.2	2.5	3.4	18.3	40.0
Placoid row	21	12.5	–	24.0	42.0	–	56.9	18.9	49.4	3.1	3.6	24.0	52.5
Claw 1 lengths
External primary branch	18	6.0	–	9.4	17.6	–	22.5	7.5	20.0	1.0	1.2	?	?
External secondary branch	18	5.0	–	8.0	13.3	–	18.1	6.1	16.3	0.8	1.1	?	?
Internal primary branch	21	5.7	–	9.1	17.1	–	21.0	7.3	19.1	0.9	0.9	9.1	19.9
Internal secondary branch	21	4.3	–	8.1	13.9	–	17.6	6.0	15.7	0.9	1.0	8.1	17.6
Claw 2 lengths
External primary branch	20	6.2	–	9.7	19.1	–	22.8	7.9	20.7	1.0	1.1	9.7	21.1
External secondary branch	20	5.3	–	8.9	15.1	–	19.4	6.5	17.0	0.9	1.2	8.9	19.4
Internal primary branch	20	5.7	–	9.1	18.0	–	21.8	7.2	19.0	0.9	0.9	9.1	19.8
Internal secondary branch	20	4.5	–	7.8	14.4	–	18.1	6.1	16.0	0.8	1.2	6.7	14.6
Claw 3 lengths
External primary branch	20	6.4	–	9.7	19.3	–	23.0	7.9	20.8	1.0	1.0	9.7	21.1
External secondary branch	20	5.3	–	8.4	14.9	–	19.0	6.3	16.7	0.8	1.1	7.8	17.0
Internal primary branch	20	5.8	–	9.1	17.1	–	21.3	7.3	19.2	0.9	1.0	9.1	19.8
Internal secondary branch	20	4.7	–	7.9	14.1	–	17.8	6.1	16.1	0.7	0.9	6.9	15.2
Claw 4 lengths
Anterior primary branch	19	6.6	–	10.8	16.8	–	27.5	8.8	23.3	1.2	2.4	9.9	21.6
Anterior secondary branch	19	5.1	–	8.4	16.3	–	19.9	7.0	18.4	0.9	1.1	7.5	16.3
Posterior primary branch	16	7.6	–	11.6	22.4	–	29.0	9.5	25.4	1.2	1.4	?	?
Posterior secondary branch	15	5.4	–	8.0	16.4	–	20.1	6.8	18.2	0.8	1.0	?	?
			µm			pt		µm	pt	µm	pt	µm	pt
Body length	10	264	–	521	808	–	1119	366	948	87	121	521	1119
Buccopharyngeal tube
Buccal tube length	10	30,1	–	46,5		–		38,3	–	5,7	–	46,5	–
Stylet support insertion point	10	22,5	–	35,2	74,7	–	77,6	29,0	75,8	4,5	0,8	35,2	75,6
Buccal tube external width	10	4,0	–	7,6	13,0	–	18,2	5,6	14,6	1,2	1,4	7,2	15,5
Buccal tube internal width	10	2,9	–	6,0	9,6	–	14,4	4,3	11,1	1,1	1,5	5,6	12,0
Ventral lamina length	9	20,0	–	32,1	61,7	–	69,0	25,4	66,1	4,4	2,3	32,1	69,0
Placoid lengths
Macroplacoid 1	10	3,4	–	6,4	10,9	–	15,3	5,0	12,9	1,1	1,6	6,4	13,7
Macroplacoid 2	10	3,0	–	5,7	9,7	–	12,4	4,1	10,6	0,9	0,8	5,4	11,5
Macroplacoid 3	10	3,0	–	6,4	9,9	–	14,3	4,9	12,6	1,1	1,3	6,4	13,7
Microplacoid	10	2,0	–	4,5	6,5	–	9,9	3,3	8,5	0,8	1,0	4,5	9,7
Macroplacoid row	10	11,2	–	21,3	37,4	–	46,6	16,2	41,9	3,4	3,1	21,3	45,7
Placoid row	10	14,3	–	27,3	47,4	–	58,9	20,5	53,2	4,2	3,7	27,3	58,6
Claw 1 heights
External primary branch	10	7,2	–	12,4	22,0	–	26,7	9,4	24,7	1,5	1,3	12,4	26,7
External secondary branch	10	5,7	–	9,6	18,5	–	23,2	7,6	19,9	1,2	1,4	9,6	20,5
Internal primary branch	10	6,8	–	12,6	22,7	–	27,0	9,3	24,2	1,6	1,3	12,6	27,0
Internal secondary branch	10	5,5	–	9,2	16,2	–	22,3	7,3	19,1	1,2	1,6	8,9	19,2
Claw 2 heights
External primary branch	10	7,5	–	13,3	23,0	–	28,5	9,8	25,6	1,7	1,6	13,3	28,5
External secondary branch	10	5,9	–	11,1	19,0	–	23,8	8,2	21,3	1,5	1,7	11,1	23,8
Internal primary branch	10	8,1	–	12,5	24,2	–	28,0	10,0	26,1	1,4	1,1	12,5	26,8
Internal secondary branch	10	5,5	–	9,0	17,9	–	24,4	7,8	20,4	1,1	1,9	9,0	19,4
Claw 3 heights												?	?
External primary branch	10	7,8	–	13,0	23,7	–	27,8	9,9	25,8	1,5	1,3	13,0	27,8
External secondary branch	10	5,6	–	9,8	17,2	–	22,4	7,7	20,1	1,4	1,6	9,8	21,0
Internal primary branch	10	7,8	–	12,6	24,2	–	28,9	9,9	25,9	1,5	1,4	12,6	27,0
Internal secondary branch	10	6,1	–	10,4	17,9	–	26,9	7,9	20,7	1,4	2,4	9,1	19,5
Claw 4 heights
Anterior primary branch	10	8,7	–	14,6	27,5	–	32,2	11,4	29,8	1,8	1,4	14,6	31,4
Anterior secondary branch	10	5,9	–	10,8	19,7	–	23,4	8,4	22,0	1,4	1,3	10,8	23,2
Posterior primary branch	10	9,5	–	13,5	27,1	–	35,1	11,8	31,1	1,6	2,4	12,6	27,1
Posterior secondary branch	10	7,4	–	11,0	20,1	–	25,3	8,9	23,5	1,3	1,7	9,8	21,0