Monatractides ventriosus

Pešić, Vladimir, Smit, Harry & Mary, Nathalie, 2015, Third contribution to the knowledge of water mites from the Comoros, with the description of two new species (Acari: Hydrachnidia), Zootaxa 3964 (4), pp. 445-459 : 451-454

Monatractides ventriosus —species complex

( Figs. 5A–E , 6A–D , 7A–E )

Material examined. Comoros , Mayotte: River Batirini, 12°45'37,7"S, 45°06'42,0"E, 22-iv-2009, 26[13 juvenile]/ 40[19 juvenile]/13 (2/2/0 mounted); River Bouyouni, upstream, 12°45'38,4"S, 45°08'46,7"E, alt. 105 m asl., 19-iv- 2009, 15[4 juveniles]/20[1 juvenile]/1; ibid., 6-ix-2011, 1/0/0 (mounted); ibid., 30-vii-2012, 5/4/0; River Bouyouni, upstream, 12°45'55,6"S, 45°08'46,7"E, alt. 105 m asl., 27-viii-2013, 1/1/0; River Bouyouni, intermediate, 12°44'55,6"S, 45°08'36,4"E, alt. 40 m asl., 2-ix-2013, 2/1/0; ibid., 30-vii-2012, 2/0/0; River Bouyouni, downstream, 12°44'25,3"S, 45°08'33,3"E, alt. 10 m asl., 30-vii-2012, 3[juvenile]/3/0; ibid., 2-ix-2012, 2[1 juvenile]/1/1; River Chirini, upstream, 12°46'39,7"S, 45°06'16,4"E, 22-iv-2009, 5[1 juvenile]/2[1 juvenile]/0; ibid., 28-ix-2011, 0/1/0; River Chirini, downstream, 12°46'39,7"S, 45°06'6,4"E, alt. 25 m asl., 31-vii-2012, 3/5/0; River Combani, intermediate, 12°46'17,2"S, 45°08'51,1"E, alt. 140 m asl., 30-viii-2013, 0/1[juvenile]/0; ibid., 8-ix- 2011, 1/0/0; ibid., 29-vii-2012, 0/3/0; River Dembeni, 20-iv-2009, 1/3/0; River Dembéni, 12°50'31,9"S, 45°10'22,9"E, alt. 10 m asl., 5-ix-2011, 0/1/0; Dembéni River, downstream, 12°50'31,9"S, 45°10'22,0"E, alt 10 m, 28-vii-2012, 0/1/0; River Djalimou, downstream, 12°57'14,4"S, 45°06'51,7"E, alt. 15 m asl., 31-viii-2013, 2/1/0; River Gouloué, 12°47'27,25"S, 45°11'22,9"E, 15-iv-2009, 1[juvenile]/0/0; River Gouloué, upstream, 12°47'27,2"S, 45°11'22,9"E, alt. 610 m asl., 5-ix-2011, 8/7/0 (1/1/0 mounted); River Gouloué, intermediate, 12°47'23,4"S, 45°11'32,0"E, alt. 110 m asl., 29-vii-2012, 1/0/1; ibid., 1-ix-2013, 11/24[1 juvenile]/0; River Mroni Mouala, 12°46'17,2"S, 45°08'51,1"E, 20-iv-2009, 3[1 juvenile]/0/0; River Koualé, 12°47'49,7"S, 45°11'08,6"E, 21-iv-2009, 1/0/0; River Koualé, upstream, 12°48'19,5"S, 45°09'49,7"E, alt. 135 m asl., 22-iv-2009, 2[1 juvenile]/1/0; ibid., 31- vii-2012, 7/10[1 juvenile]/0; ibid., 7-ix-2011, 1/1/0; ibid., 30-viii-2013, 5[1 juvenile]/2/0; River Koualé, intermediate, 12°47'49,7"S, 45°11'8,6"E, alt. 50 m asl., 9-ix-2011, 5[2 juveniles]/9[1 juvenile]/0; ibid., 1-viii-2012, 3/4/0; ibid., 29-viii-2013, 3[1 juvenile]/6[3 juveniles]/0; River Koualé, downstream, 12°48'20,4"S, 45°11'54,4"E, alt. 10 m asl., 1-viii-2012, 0/1/0; ibid., 29-viii-2013, 1/0/0; ibid., 9-ix-2011, 0/1/0; River Koualé, tributary, 12°47'57,35"S, 45°09'51,2"E, 21-iv-2009, 1/0/0; River Longoni, 12°44'20,05"S, 45°09'53,6"E, 16-iv-2009, 1/5/0; River Ourovéni, intermediate, 12°47'47,05"S, 45°08'22,1"E, 20-iv-2009, 0/1[juvenile]/0; River Ourovéni, 12°47'47,0"S, 45°08'22,1"E, alt. 80 m asl., 29-vii-2012, 1/0/0; River Ourovéni, downstream, 12°48'29,9"S, 45°07'39,4"E, alt. 40 m asl., 17-iv-2009, 1/2[1 juvenile]/0; ibid., 7-ix-2011, 5/4/0; ibid., 28-vii-2012, 8[juvenile]/ 12[juvenile]/0; ibid., 1-ix-2013, 3/4/0.

Morphology. General features—Idiosoma roundish; shoulder platelets elongated (shoulder/frontal platelet L ratio 1.5–1.7); frontal margin medially with large anterolaterally pointed apodemes ( Figs. 5A , 6A ); Cxgl-4 located far anteriorly, near tips of Cx-I; gnathosomal bay moderately deep, narrow, V-shaped, three pairs of knob-like protrusions at the lateral margins of gnathosomal bay ( Figs. 5C , 6C ); suture line of Cx-IV distinct, originating from lateral edge of genital field; posterior line of primary sclerotization close to posterior margin of genital field; excretory pore posterior to the line of primary sclerotization, Vgl–2 posterior to excretory pore; distal margin of P- 3 and P-4 medially with several pointed extensions; P-4 with two ventral setae, one very long and away from distal edge ( Figs. 5D , 6D ). Male: medial margin of Cx-II/III relatively short; genital field subrectangular; ejaculatory complex ( Figs. 5E , 7C ) slightly elongated with small proximal chamber. Female: genital field pentagonal, anteriorly rounded, laterally straight, tapering posteriorly.

Measurements: Table 1 .

Remarks. Since the original description of Monatractides ventriosus based on a single female from Cameroon ( K. Viets, 1916), water mites from different regions of Africa have been assigned to this species. As stated by many authors ( Cook 1966, Goldschmidt & Smit 2009, Smit et al. 2010, Pešić & Smit 2014), the variability of populations from different regions of the whole distribution area needs to be examined to clarify the taxonomy. Pešić & Smit (2014) recently stated that specimens from Western Africa ( Ghana and Liberia) assigned to M. ventriosus probably represent an undescribed species.

Comparison with figures from the original description of K. Viets (1916) suggests that specimens in our study cannot be conspecific with M. ventriosus . The ventral setae on P- 4 in the type specimen are short, not reaching the tip of P-5. In our specimens, one of P-4 ventral setae is characteristically very long and away from the distal edge, as illustrated by Lundblad (1952) for M. ventriosus from Kenya. Moreover, the specimens from our study resemble the latter specimens in the shape of the ejaculatory complex (elongated, with a small proximal chamber, see Lundblad 1952: fig. 39E). Lundblad (1952) synonymized M. lemnius ( Lundblad, 1927) and M. elgonensis ( Lundblad, 1941) , both decribed from Kenya ( Lundblad 1927 and Lundblad 1941, respectively) with M. ventriosus . Monatractides elgonensis differs from M. lemnius in smaller dimensions of the genital field and suture line of Cx-IV medially starting from posterior margin of genital field in a more right angle to the main idiosoma margin, features which may not be reliable taxonomic characters ( Lundblad 1952). It is likely the specimens from our material from Comoros and those described from Kenya ( Lundblad 1952) represent the same species ( M. lemnius ) or possibly a group of similar species. This should be clarified by additional sampling of material from Kenya, and/or by the application of molecular techniques.

Figures

FIGURE 5 A – E. Monatractides ventriosus — species complex, male, River Gouloué: A = frontal margin of idiosoma, dorsal view; B = dorsal shield; C = idiosoma, ventral view; D = palp, medial view; E = ejaculatory complex. Scale bars = 100 Μm.

FIGURE 6 A – D. Monatractides ventriosus — species complex, female, River Gouloué: A = frontal margin of idiosoma, dorsal view; B = dorsal shield; C = idiosoma, ventral view; D = palp, lateral view. Scale bars = 100 Μm.

FIGURE 7 A – E. Photographs of Monatractides ventriosus — species complex (A – C = male, D – E = female), River Gouloué: A, D = dorsal shield; B, E = idiosoma, ventral view; C = ejaculatory complex.

Tables

TABLE 1. Measurements of Monatractides ventriosus — species complex from Comoros.

	Gouloué River, ♂ n = 1	Batirini River, ♂ n = 2	Gouloué River, ♀ Batirini River, ♀ n = 1 n = 2
Idiosoma L Idiosoma W Idiosoma L/W ratio Ds L Ds W Ds L/W ratio	769 656 1.17 661 531 1.25	738–744 622–628 1.19 638–650 488–500 1.3–1.31	810 788–809 700 650–696 1.16 1.16–1.21 700 669–713 550 513–580 1.27 1.23–1.3
Dp L Sh platelet L Sh platelet W Sh platelet L/W	600 206–209 84–90 2.3–2.45	581–600 194–203 83–89 2.28–2.37	633 606–647 209–211 193–219 94 84–95 2.23–2.25 2.3–2.34
F platelet L F platelet W F L/W ratio Sh platelet/F platelet L ratio Gnathosomal bay L Cx-I L	134 89–91 1.48–1.5 1.53–1.56 150 284	120–125 78–84 1.42–1.56 1.6–1.67 157–150 272–284	125–128 122–131 97–98 84–91 1.27–1.32 1.44–1.48 1.63–1.69 1.54–1.67 153 144–165 291 267–300
Cx-I mL Cx-II+III mL Cx-1 L/Cx-II+III mL Cx-I mL/Cx-II+III mL ratio	134 75 3.8 1.8	125–134 70–88 3.1–4.1 1.4–1.9	138 122–135 56 64–69 5.2 3.9–4.7 2.5 1.8–2.1
Genital field L Genital field W Gf L/W ratio Dist gf—expo Dist gf—cauda	150 125 1.2 156 256	134–135 116 1.16–1.17 131–150 228–250	181 169–178 163 156–169 1.12 1.06–1.08 170 158–180 275 264–269
Ec L Gnathosoma vL Chelicera L Palp, total L	184 146 195 220	189–194 151–153 205 211	- - 166 160 205 205 223 210
P-1 dL/H P-2 dL/H P-3 dL/H P-4 dL/H P-5 dL/H P-1 dL/H ratio	25/27 60/43 42/35 60/23 33/14 0.91	22/26–27 56–58/43 40/32 55–59/21–22 30–32/14 0.8	23/28 23–25/26–28 61–62/45 57–62/42–44 44/36 41–42/32–35 60/25 57–59/22–23 35/14 32/14 0.83 0.83–0.94
P-2 dL/H ratio P-3 dL/H ratio P-4 dL/H ratio P-5 dL/H ratio	1.4 1.19 2.6 2.4	1.31–1.34 1.24 2.7 2.1–2.3	1.36–1.38 1.37–1.4 1.22 1.17–1.26 2.4 2.55–2.57 2.5 2.3
dL P-2/P-4 ratio I-L-4 L I-L-5 L I-L-6 L I-L-6 H I-L-6 L/H ratio	1.0 106 99 95 35 2.7	0.99–1.02 100–103 97–102 94–99 34–36 2.7–2.8	1.02 1.0–1.04 104 110 103 108 100 100 36 37 2.78 2.7