Estellacarus Habeeb, 1954

Smith, Ian M., Cook, David R. & Gerecke, Reinhard, 2015, Revision of the status of some genus-level water mite taxa in the families Pionidae Thor, 1900, Aturidae Thor, 1900, and Nudomideopsidae Smith, 1990 (Acari: Hydrachnidiae), Zootaxa 3919 (1), pp. 111-156 : 147-148

Genus Estellacarus Habeeb, 1954

Estellacarus: Cook, 1974a , pp. 341–342, figs. 1446, 1448, 1450–1452, 1454. Estellacarus: Smith, 1984 , pp. 313–314, figs. 17–24.

Estellacarus: Smith & Cook, 1991 , pp. 553, 577.

Estellacarus: Smith et al., 2001 , pp. 580, 614, figs. 157–159, 358, 362. Estellacarus: Smith et al., 2010 , pp. 523, 555, figs.15.157–15.159, 15.359, 15.363.

Diagnosis. Larva (modified from Smith 1984 and based upon larvae of E. unguitarsus (Habeeb) , only species in genus): Third coxal plate with medial coxal apodeme present but small and transverse muscle attachment scar absent. Posterior edge of third coxal plate bearing prominent pointed projection. Excretory pore plate much larger than excretory pore and nearly triangular in shape, bearing setae ps1, ps2, and h2 posterolaterally with ps2 displaced anteriorly and medially. Numbers of setae on leg segments as follows: ITi 8 (seta Ti10 absent); ITa 12 (seta Ta14 absent); IITa 12 (seta Ta14 absent).

Adults (modified from Cook 1974a): Character states of Brachypoda -like mites. Dorsal shield of males without a slight bulge posterior to midlength and lacking enlarged glandularia with extremely long associated setae. Ventral shield of males lacking a pronounced ridge extending anterolaterally from genital field. Fourth coxal plate with opening for insertion of fourth leg lacking condyles; bearing a short ridge extending posteriorly from region of insertion of fourth legs. Genital field bearing three pairs of acetabula; genital field of males located near posterior edge of ventral shield and relatively compact, with acetabula not extending laterally beyond level of insertion of fourth leg and without a patch of long setae immediately lateral to acetabula. Excretory pore borne on separate small platelet posterior to dorsal shield. Fourth leg of males with genu and tibia unmodified, and tarsus short and greatly expanded distally and bearing unmodified claw socket and claws. Pedipalp femur bearing a distoventral projection and tibia bearing a thick seta on a ventral projection.

Type species. Estellacarus unguitarsus Habeeb.

Species included. Estellacarus unguitarsus Habeeb (North America) (monobasic).

Distribution. North America.

Discussion. Cook (1974a) considered Estellacarus to be a distinct genus. This treatment was followed by Smith (1984), Smith & Cook (1991), and Smith et al. (2001, 2010), and by us here.