Sperchon squamosus Kramer, 1879

Martin, Peter, 2006, On the morphology and classification of larval water mites (Hydrachnidia, Acari) from springs in Luxembourg, Zootaxa 1138, pp. 1-44 : 17-18

Sperchon squamosus Kramer, 1879

Records ( Table 2): Benthos samples at ten spring sites in Gutland and in Ösling, 48 individuals ( Gerecke et al. 2005). E2 58 larvae, E3 93 larvae, E5 1 larva, parasitic on chironomids. Attribution based on individuals reared from a female from a small lowland stream in the German lowlands (Himmelreichbach, see Martin 1997).

Descriptions of larvae: Lundblad (1927), MotaŞ (1961), Ullrich (1976).

Description (n = 5, Himmelreichbach): Idiosoma ovate; in non­engorged specimens and to a lesser extent in slightly engorged specimens with distinct distal indentation ( Figs. 28, 29 ). Length/width of idiosoma 234–261 (251)/174–198 (187).

Dorsal idiosoma ( Fig. 28 ): Dp relatively large and ovate, anteriorly and medially with a fine lineation, the lines meeting each other laterally and posteriorly and building almost a rhombic pattern. Length/width Dp 202–245 (230)/153–168 (161), length eye capsule 36– 43 (39), Mp2­Amdp 49–57 (53), Mp1­Mp1 55–62 (60), Mp2­Mp2 48–58 (53), Lp1­Lp1 34–40 (37), Lp2­Lp2 100–106 (103), Mp1­Lp 1 11–14 (12), Mp2­Lp2 33–36 (34), Mp1­ Mp2 37–40 (39), Lp1­Lp2 40–42 (41), Mp 1 25–32 (28), Mp 2 20–35 (26), Lp1 72–96 (87), Lp2 140–150 (146), Hu 120–140 (134), Mh1 118–150 (141), Mh2 105–140 (127), Mh3 103–113 (109), Mh4 78–103 (94), Lh1 128–140 (134), Lh2 108–118 (114), Lh3 85–105 (92).

Ventral idiosoma ( Fig. 29 ): Length/width CX­I 88–93 (91)/38–45 (42), CX­II 75–93 (85)/58–65 (61), CX­III 133–150 (143)/88–98 (93), coxal plates with an alveolar pattern, between the median margins of the coxal plates III, one or two small sclerites, urstigmata rounded, C1­C2 53–57 (55), C1­Mmcp 20–25 (23), C4­Pmcp 105–132 (144), C1­C4 40– 55 (48), C1 55–65 (60), C2 82–105 (90), C3 80–89 (83), C4 74–94 (81), Expp relative large and pronounced, length/width 20–22 (21)/19–22 (21), E1­ E 1 8 –11 (9), E2­ E 2 15 –19 (16), E1­ E 2 11 –14 (13), E 1 15 –22 (18), E 2 21 –42 (26), V1 59 –68 (63), V2 62 –76 (68), V3 80 –92 (86), V4 85 –94 (90).

Gnathosoma: Base (n=4) 90–97 (95), length chelicera ( Fig. 30 ) (n=3) 83–87 (85), chela 14–16 (15), length/width P 2 28–40 (36)/28–30 (29), P 3 30–35 (32)/26–29 (27), claw (n=4) 12–18 (15), palpal seta C3 82–105 (98), C4 57–72 (63), C5 67–79 (73), lateral seta 79–90 (86).

Legs: First segments with a little pronounced transverse lineation, some of the other segments slightly lineated.

Leg I ( Fig. 31 ): Total length (n=5) 276–300 (289), length/height I­L1 35–38 (36)/29– 30 (30), I­L2 43–48 (46)/30–31 (31), I­L3 56–60 (59)/25–28 (26), I­L4 66–72 (70)/24–25 (25), I­L5 76–82 (78)/ 19–20 (20).

Leg II ( Fig. 32 ): Total length 311–326 (319), length/height II­L1 44–46 (45)/28–30 (29), II­L2 49–51 (50)/29–30 (30), II­L3 61–63 (62)/25–27 (26), II­L4 75–82 (79)/24–28 (25), II­L5 82–84 (83)/ 19–20 (20).

Leg III ( Fig. 33 ): Total length 376–436 (418), length/width III­L1 72–75 (74)/29–31 (30), III­L2 63–68 (66)/27–30 (28), III­L3 85–91 (89)/22–24 (23), III­L4 104–108 (106)/ 22–24 (23), III­L5 52–94 (83)/17–18 (18).

Diagnostic characters of larvae: Structure of the Dp (laterally and posteriorly with a rhombic pattern).

Remarks: Previous descriptions of Sperchon squamosus often lack measurement data and/or accurate illustrations.

Figures

FIGURES 28 – 30. Sperchon squamosus (original). Fig. 28: dorsal idiosoma, Fig. 29: ventral idiosoma, Fig. 30: chelicera. Scale bars: 28, 29: 100 µm, 30 50 µm.

FIGURES 31 – 33. Sperchon squamosus (original). Fig. 31: I­L, Fig. 32: II­L, Fig. 33: III­L. Scale bar 100 µm.