Diamphidaxona chiricahua, Smith, Ian M. & Cook, David R., 2006

Smith, Ian M. & Cook, David R., 2006, North American species of Diamphidaxona (Acari: Hydrachnida: Hygrobatidae), Zootaxa 1279, pp. 1-44 : 11-12

Diamphidaxona (s. s.) chiricahua sp. nov.

( Figs. 35–41 )

Description. Character states of Diamphidaxona (s. s.). Dorsal edge of camerostome rounded anteriorly and not projecting to anterior end of idiosoma ( Figs. 37, 40 ). Pedipalps with tibia bearing one ventral seta and tarsus with ventral spine­like seta bearing three straight or slightly curved denticles ventrally ( Fig. 39 ). Dorsal shield with anterior plate of same width as posterior plate and rounded anteriorly ( Fig. 35 ). Ventral shield with suture lines between third and fourth coxal plates with medial loops shallow and lateral loops Ushaped and open anteriorly ( Figs. 37, 40 ). Projections covering insertions of fourth pair of legs with anterior extensions long and directed anteriorly parallel to edges of ventral shield ( Figs. 37–40 ). Genital field of males fused with ventral shield but with suture line visible ( Fig. 37 ). Measurements: Male (n=4): Length/width anterior dorsal plate 168–181/ 272–302 (173/282), length/width posterior dorsal plate 322–366/277–302 (361/287), length/width ventral shield 475–520/327–351 (490/337), length/width genital field 79–94/ 144–168 (94/153). Lengths pedipalp segments: Tr 18–20 (18), Fe 65–73 (70), Ge 50–55 (50), Ti 70–73 (73), Ta 33–35 (35). Lengths leg segments: ITr 33–39 (39), IBFe 63–78 (68), ITFe 68–75 (68), IGe 83–88 (83), ITi 85–88 (85), ITa 88–100 (95); IITr 35–43 (40), IIBFe 63–70 (65), IITFe 63–73 (65), IIGe 75–83 (75), IITi 78–85 (78), IITa 88–100 (90); IIITr 40–45 (42), IIIBFe 58–65 (63), IIITFe 60–69 (60), IIIGe 75–80 (75), IIITi 80–85 (83), IIITa 88–95 (93); IVTr 93–100 (93), IVBFe 88–93 (88), IVTFe 103–113 (103), IVGe 118–135 (118), IVTi 120–130 (120), IVTa 113–128 (118). Female (n=5): Length/width anterior dorsal plate 188–213/301–376, length/width posterior dorsal plate 337–396/ 307–366, length/width ventral shield 490–579/366–446, width genital field 139–173. Lengths pedipalp segments: Tr 20–25, Fe 80–88, Ge 55–63, Ti 80–88, Ta 35–41. Lengths leg segments: ITr 48–50, IBFe 70–85, ITFe 75–88, IGe 90–105, ITi 88–103, ITa 103–115; IITr 48–50, IIBFe 75–80, IITFe 75–81, IIGe 85–98, IITi 88–98, IITa 96–110; IIITr 48–50, IIIBFe 68–85, IIITFe 70–83, IIIGe 83–98, IIITi 88–103, IIITa 95–113; IVTr 95–118, IVBFe 95–108, IVTFe 113–128, IVGe 133–155, IVTi 133–150, IVTa 128–145.

Types. Holotype: Male from Turkey Creek (West Turkey Creek) at Sycamore Campground, Chiricahua Mountains east of Sunizona, Cochise Co. , Arizona on 10 May 2000 by IMS (slide, CNC). Paratypes: Arizona: Cochise Co. : Chiricahua Mountains east of Sunizona: same data as holotype — 2 females, 1 deutonymph (slides, CNC); same locality as holotype, 15 May 1991, IMS — 1 female (slide, CNC); 15 October 1993, IMS — 2 males, 3 females (slides, CNC); 11 May 1998, IMS — 1 female (slide, CNC). Chiricahua Mountains west of Portal, Cave Creek beside Forest Road 42 near Stewart Campground, 9–11 October 1993, IMS — 1 female (slide, CNC).

Etymology. Named for the Chiricahua Mountains where all known specimens of this species have been collected.

Distribution. Streams in the Chiricahua Mountains of southeastern Arizona.

Remarks. Adults of Diamphidaxona chiricahua resemble those of the preceding two species and the following three species in that the projections covering the insertions of the fourth pair of legs are long and extend anteriorly parallel to the edges of the ventral shield, but differ from all other species except D. cavecreekensis in that the suture lines between the third and fourth coxal plates have the medial loops relatively shallow. They differ from adults of D. cavecreekensis in being much larger in size with the posterior dorsal plate slightly narrowed near its midlength and the leg segments relatively long and slender.

Figures

FIGURES 35 – 41. Diamphidaxona (s. s.) chiricahua sp. nov., adults. 35, dorsal shield, female; 36, distal segments of leg IV, female; 37, ventral shield and genital field, male; 38, leg I, female; 39, pedipalp, female; 40, ventral shield and genital field, female; 41, gnathosoma, lateral view, female.