Diamphidaxona cramerae, 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 : 5-6

Diamphidaxona (s. s.) cramerae sp. nov.

( Figs. 1–7 )

Description. Character states of Diamphidaxona (s. s.). Dorsal edge of camerostome strongly acutely angled anteriorly and projecting to or slightly beyond anterior end of idiosoma ( Figs. 3, 6 ). Pedipalps with tibia bearing one ventral seta and tarsus with ventral spine­like seta smooth ( Fig. 5 ). Dorsal shield with anterior plate approximately equal in width to posterior plate and slightly pointed anteriorly ( Fig. 1 ). Ventral shield with suture lines between third and fourth coxal plates with medial loops deeply arched and lateral loops drop­shaped and closed anteriorly ( Figs. 3, 6 ). Projections covering insertions of fourth pair of legs with anterior extensions moderately long and directed anterolaterally ( Figs. 3, 6 ). Genital field of males separated from ventral shield by distinct band of membranous integument ( Fig. 3 ). Measurements: Male holotype (n=1): Length/width anterior dorsal plate 119/198, length/width posterior dorsal plate 223/200, length/width ventral shield 322/233, length/width genital field 50/82. Lengths pedipalp segments: Tr 10, Fe 28, Ge 20, Ti 30, Ta 21. Lengths leg segments: ITr 28, IBFe 33, ITFe 38, IGe 45, ITi 45, ITa 55; IITr 30, IIBFe 30, IITFe 35, IIGe 43, IITi 43, IITa 53; IIITr 30, IIIBFe 33, IIITFe 35, IIIGe 45, IIITi 49, IIITa 58; IVTr 63, IVBFe 53, IVTFe 58, IVGe 65, IVTi 68, IVTa 65. Female (n=3): Length/width anterior dorsal plate 131–139/205–233, length/ width posterior dorsal plate 233/210–228, length/width ventral shield 351–361/248–260, width genital field 89–100. Lengths pedipalp segments: Tr 10–13, Fe 30, Ge 23–25, Ti 35–38, Ta 20–23. Lengths leg segments: ITr 28–33, IBFe 35–38, ITFe 43–45, IGe 50–53, ITi 53–55, ITa 60–63; IITr 30–35, IIBFe 35, IITFe 38, IIGe 50–53, IITi 55–58, IITa 63–65; IIITr 33, IIIBFe 35–38, IIITFe 38, IIIGe 50–53, IIITi 55–58, IIITa 63–65; IVTr 65–70, IVBFe 58–59, IVTFe 63, IVGe 73, IVTi 70–73, IVTa 68–75.

Types. Holotype: Male from Little Creek beside Little Creek Trail off Rt. 15, ca. 65 km north of Rt. 180 in Silver City, Catron Co., New Mexico on 10 July 1987 by IMS (slide, CNC). Paratypes: Arizona: Cochise Co. : Chiricahua Mountains west of Porta: Cave Creek below dam at Herb Martyr Campground off Forest Road 42A, 1 May 2001, IMS— 1 female (slide, CNC); Cave Creek below dam at John Hand Picnic Area off Forest Road 42A, 15 September 2001, IMS— 1 female (slide, CNC). Missouri: Crawford Co.: Huzzah Creek at Red Bluff Campground off Road V east of Davisville, 26 June 1987, IMS— 1 female (slide, CNC).

Etymology. Named for the Cristina Cramer in recognition of her contributions to knowledge of the systematics of Mexican water mites.

Distribution. Streams from Missouri to southwestern New Mexico and southeastern Arizona.

Remarks. Adults of Diamphidaxona cramerae differ from those of all other known North American species of Diamphidaxona in that the suture lines between the third and fourth coxal plates have the lateral loops drop­shaped and closed anteriorly. They also differ from all other North American species, except D. imamurai , in that the pedipalps are relatively small and the dorsal edge of the camerostome is strongly acutely angled anteriorly and extends to or beyond the anterior edge of the idiosoma.

Figures

FIGURES 1 – 7. Diamphidaxona (s. s.) cramerae sp. nov., adults. 1, dorsal shield, female; 2, distal segments of leg IV, male; 3, ventral shield and genital field, male; 4, leg I, female; 5, pedipalp, female; 6, ventral shield and genital field, female; 7, gnathosoma, lateral view, female.