Diamphidaxona chihuahua, 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 : 8-9

Diamphidaxona (s. s.) chihuahua sp. nov.

( Figs. 16–22 )

Description. Character states of Diamphidaxona (s. s.). Dorsal edge of camerostome rounded anteriorly and not projecting to anterior end of idiosoma ( Figs. 18, 21 ). Pedipalps with tibia bearing one ventral seta and tarsus with ventral spine­like seta smooth ( Fig. 20 ). Dorsal shield with anterior plate of same width as posterior plate and slightly pointed anteriorly ( Fig. 16 ). Ventral shield with suture lines between third and fourth coxal plates with medial loops deeply arched and lateral loops U­shaped and open anteriorly ( Figs. 18, 21 ). Projections covering insertions of fourth pair of legs with anterior extensions short and directed laterally to edges of ventral shield ( Figs. 18, 21 ). Genital field of males separated from ventral shield by distinct band of membranous integument ( Fig. 18 ). Measurements: Male (n=5): Length/width anterior dorsal plate 139–149/218–238 (149/ 223), length/width posterior dorsal plate 233–252/218–228 (252/228), length/width ventral shield 342–362/257–272 (362/272), length/width genital field 54–59/104–109 (55/ 109). Lengths pedipalp segments: Tr 15–18 (18), Fe 53–57 (57), Ge 33–35 (35), Ti 55–60 (57), Ta 33–35 (35). Lengths leg segments: ITr 33–40 (38), IBFe 45–50 (50), ITFe 43–45 (44), IGe 53–55 (55), ITi 55–58 (55), ITa 63–65 (65); IITr 33–38 (35), IIBFe 43–45 (45), IITFe 40–45 (43), IIGe 50–53 (53), IITi 53–55 (55), IITa 63 (63); IIITr 33–40 (40), IIIBFe 43–44 (44), IIITFe 40–45 (45), IIIGe 53 (53), IIITi 58–63 (63), IIITa 65–69 (68); IVTr 80–85 (85), IVBFe 63–68 (65), IVTFe 70–78 (78), IVGe 80–83 (83), IVTi 85–86 (85), IVTa 78–81 (81). Female (n=5): Length/width anterior dorsal plate 144–149/210–240, length/width posterior dorsal plate 248–272/208–245, length/width ventral shield 356–396/257–292, width genital field 92–99. Lengths pedipalp segments: Tr 16–19, Fe 53–60, Ge 33–38, Ti 53–60, Ta 30–35. Lengths leg segments: ITr 35–38, IBFe 48–53, ITFe 43–48, IGe 53–60, ITi 54–60, ITa 61–68; IITr 34–40, IIBFe 44–50, IITFe 41–48, IIGe 48–55, IITi 50–58, IITa 60–68; IIITr 35–38, IIIBFe 43–50, IIITFe 41–48, IIIGe 50–55, IIITi 54–63, IIITa 64–70; IVTr 75–85, IVBFe 63–70, IVTFe 70–80, IVGe 75–88, IVTi 80–91, IVTa 75–83.

Types. Holotype: Male from Turkey Creek (West Turkey Creek) at Sycamore Campground, Chiricahua Mountains east of Sunizona, Cochise Co. , Arizona on 15 July 1987 by IMS (slide, CNC). Paratypes: Arizona: Cochise Co. : Chiricahua Mountains east of Sunizona: same data as holotype— 1 male, 1 female (slides, CNC); same locality as holotype, 15 May 1991, IMS— 7 males, 10 females (slides, CNC); 5 May 1998, IMS— 5 females (slides, CNC); 11 May 1998, IMS — 5 males, 5 females (slides, CNC); 1 October 1999, IMS — 1 male, 2 females (slides, CNC); 7 May 2000, IMS — 1 female (slide, CNC). Mormon Creek beside Mormon Spring Trail above Sycamore Campground, 22 September 1999, IMS — 1 female (slide, CNC). Chiricahua Mountains west of Portal: Cave Creek at and just above Stewart Campground, 16 July 1987, IMS — 1 female (slide, CNC); 3 March 1999, IMS — 1 female (slide, CNC); 24 May 2000, IMS — 1 male (slide, CNC); 9 May 2002, IMS — 1 male, 1 female (slides, CNC). Cave Creek at John Hand Picnic Area off Forest Road 42A, 5 March 1999, IMS — 3 females (slides, CNC). Cave Creek below dam at Herb Martyr Campground off Forest Road 42A, 28 April 2001, IMS — 1 female (slide, CNC). North Fork of Cave Creek beside Forest Road 42, 1.3–1.6 km above Forest Road 42A, 13–23 May 2000, IMS — 2 males, 2 females (slides, CNC); 8–14 September 2001, IMS — 1 male (slide, CNC). East Turkey Creek at junction of Forest Roads 42 and 42B between Portal and Rustler Park, 15 May 1991, IMS — 1 male, 3 females (slides, CNC). New Mexico: Catron Co.: Whitewater Creek at Whitewater Picnic Area 8 km east of Glenwood, 18 May 1991, IMS — 1 female (slide, CNC); 16 October 1993, IMS — 1 male, 1 female (slides, CNC). Little Creek beside Little Creek Trail off Rt. 15, 63 km (39 miles) north of Rt. 180 in Silver City, 13 May 2002, IMS — 1 female (slide, CNC). Grant Co.: Sapillo Creek beside Rt. 15 just south of Rt. 35 north of Silver City, 8 May 2001, IMS — 1 female (slide, CNC). Texas: Brewster Co.: Calamity Creek beside Rt. 118, 32.8 km south of Rt. 90/ 67 in Alpine, 4 October 1999, IMS — 1 male, 11 females (slides, CNC).

Etymology. Named for the Chihuahuan Desert biome where all known specimens of this species have been collected.

Distribution. Streams in the desert mountain ranges of southwestern New Mexico and southeastern Arizona.

Remarks. Adults of Diamphidaxona chihuahua differ from those of all other known North American species of Diamphidaxona (s. s.) in that the projections covering the insertions of the fourth pair of legs are short and extend laterally to the edges of the ventral shield.

Figures

FIGURES 16 – 22. Diamphidaxona (s. s.) chihuahua sp. nov., adults. 16, dorsal shield, female; 17, distal segments of leg IV, male; 18, ventral shield and genital field, male; 19, leg I, female; 20, pedipalp, female; 21, ventral shield and genital field, female; 22, gnathosoma, lateral view, female.