Torrenticola walteri Fisher & Dowling

Fisher, J. Ray, Fisher, Danielle M., Skvarla, Michael J., Nelson, Whitney A. & Dowling, Ashley P. G., 2017, Revision of torrent mites (Parasitengona, Torrenticolidae, Torrenticola) of the United States and Canada: 90 descriptions, molecular phylogenetics, and a key to species, ZooKeys 701, pp. 1-496 : 1

Torrenticola walteri Fisher & Dowling sp. n.

Material examined.

HOLOTYPE (♀): from Canada, British Columbia, Ryan Rest Area off Hwy 3, East of Yahk Moyie River, 15 Aug 2012, by IM Smith, IMS120071, DNA 2955.

PARATYPES (12 ♀; 4 ♂): California, USA: 1 ♀ and 1 ♂ from El Dorado County, Upper Truckee River (38°50'56"N, 120°1'39"W), 29 Aug 2013, by JR Fisher, JRF 13-0829-003 • 2 ♀ and 2 ♂ El Dorado County, Upper Truckee River (38°50'56"N, 120°1'39"W), 29 Aug 2013, by JR Fisher, JRF 13-0829-004 • 2 ♀ from Mono County, Humboldt-Toiyabe National Forest, West Walker River (38°21'59"N, 119°28'55"W), 31 Aug 2013, by JR Fisher, JRF 13-0831-003 • 2 ♀ from Nevada County, Tahoe National Forest, Sagehen Creek (39°26'2"N, 120°12'17"W), 26 Aug 2013, by JR Fisher, JRF 13-0826-006 • Oregon, USA: 1 ♂ (ALLOTYPE) from Douglas County, Umpqua NF, Umpqua River (43°17'28"N, 122°37'12"W), 12 Aug 2013, by JC O’Neill, & WA Nelson, JNOW 13-0812-006 • 1 ♀ from Coos County, Middle Fork of Coquille River (43°1'56"N, 124°6'1"W), 12 Aug 2013, by JR Fisher, JRF 13-0812-001 • 2 ♀ from Douglas County, Umpqua NF, Umpqua River (43°17'28"N, 122°37'12"W), 12 Aug 2013, by JC O’Neill, & WA Nelson, JNOW 13-0812-006 • 2 ♀ from Lane County, Gate Creek (44°8'48"N, 122°34'20"W), 11 Aug 2013, by JC O’Neill, & WA Nelson, JNOW 13-0811-001.

Type deposition.

Holotype (♀), allotype (♂), and other paratypes (8 ♀; 2 ♂) deposited in the CNC; other paratypes (4 ♀; 1 ♂) deposited in ACUA.

Diagnosis.

Torrenticola walteri are similar to other members of the Rusetria "Western 2-Plates" group ( T. mulleni , T. nortoni , and T. welbourni ) in having anterio-lateral platelets fused to the dorsal plate, having faint dorsal coloration, and being distributed in the west. Female T. walteri can be differentiated from T. welbourni (female only known) by having stockier pedipalp tibiae (3.09-3.23 in A32, 3.73 in A30); shorter pedipalp femora (112.5-125 in A32, 137.5 in A30); and a more elongate subcapitulum (ventral length/height: 2.21-2.34 in A32, 2.47 in A30). T. walteri can be differentiated from T. mulleni by having a slightly stockier gnathosomal bay (♀ = 1.57-1.84 in T. walteri , 1.89-2.16 in T. mulleni , ♂ = 1.55-1.73 in T. walteri , 1.77-1.93 in T. mulleni ) and by being distributed in California, Oregon and British Columbia, instead of in the Rocky Mountains (Idaho, Montana, Utah and Wyoming). Additionally, male T. walteri can be differentiated from male T. mulleni by having a shorter genital field (115-117.5 in A32, 130-140 in A31), and female T. walteri can be differentiated from female T. mulleni by having a shorter medial suture (10-12.5 in T. walteri , 20-22.5 in T. mulleni ). Female T. walteri can be differentiated from female T. nortoni by having slightly shorter pedipalp femora with respect to genua (1.52-1.64 in T. walteri , 1.69-1.82 in T. nortoni ) and slightly stockier anterio-medial platelets (2.58-2.72 in T. walteri , 2.74-3.06 in T. nortoni ). Male T. walteri can be differentiated from male T. nortoni by having longer pedipalp femora (95-100 in T. walteri , 85-92.5 in T. nortoni ) and slightly more elongate pedipalp tibiae (3.05-3.10 in T. walteri , 2.73-3.0 in T. nortoni ).

Description.

Female (Figure 271) (n = 5) (holotype measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (580-640 (590) long; 420-450 (420) wide) ovoid with orange coloration separated into anterior and posterior portions, occasionally faint. Anterio-medial platelets (120-137.5 (120) long; 45-51.25 (45) wide). Anterio-lateral platelets (157.5-190 (157.5) long; 55-65 (55) wide) fused with dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 300-325 (300)). Dorsal plate proportions: dorsum length/width 1.35-1.44 (1.40); dorsal width/distance between Dgl-4 1.37-1.45 (1.40); anterio-medial platelet length/width 2.58-2.72 (2.67); anterio-lateral platelet length/width 2.63-3.27 (2.86); anterio-lateral/anterio-medial length 1.29-1.46 (1.31).

Gnathosoma - Subcapitulum (305-335 (317.5) long (ventral); 223-243 (224) long (dorsal); 135-147.5 (137.5) tall) colorless. Rostrum (122.5-127.5 (123.75) long; 45-50 (47.5) wide). Chelicerae (304-328 (304) long) with curved fangs (55.75-64 (63) long). Subcapitular proportions: ventral length/height 2.21-2.34 (2.31); rostrum length/width 2.45-2.72 (2.61). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (47.5-52.5 (50) long); femur (112.5-125 (115) long); genu (70-82.5 (70) long); tibia (85-88.75 (88.75) long; 27.5-27.5 (27.5) wide); tarsus (17.5-20 (20) long). Palpomere proportions: femur/genu 1.52-1.64 (1.64); tibia/femur 0.70-0.77 (0.77); tibia length/width 3.09-3.23 (3.23).

Venter - (690-730 (725) long; 467-520 (467) wide) colorless. Gnathosomal bay (141.25-175 (157.5) long; 86.25-95 (86.25) wide). Cxgl-4 subapical. Medial suture (10-12.5 (10) long). Genital plates (185-197.5 (197.5) long; 158.75-181.25 (180) wide). Additional measurements: Cx-1 (250-300 (285) long (total); 102-127 (119) long (medial)); Cx-3 (313-362 (313) wide); anterior venter (140-158.75 (150) long). Ventral proportions: gnathosomal bay length/width 1.57-1.84 (1.83); anterior venter/genital field length 0.75-0.86 (0.76); anterior venter length/genital field width 0.83-0.96 (0.83); anterior venter/medial suture 11.20-15.88 (15.00).

Male (Figure 272) (n = 4) (allotypic measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (490-510 (510) long; 340-350 (350) wide) ovoid with orange coloration separated into anterior and posterior portions, occasionally faint. Anterio-medial platelets (105-115 (115) long; 40-42.5 (42.5) wide). Anterio-lateral platelets (125-142.5 (142.5) long; 47.5-52.5 (52.5) wide) fused with dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 255-270 (270)). Dorsal plate proportions: dorsum length/width 1.43-1.46 (1.46); dorsal width/distance between Dgl-4 1.30-1.33 (1.30); anterio-medial platelet length/width 2.63-2.71 (2.71); anterio-lateral platelet length/width 2.63-2.71 (2.71); anterio-lateral/anterio-medial length 1.19-1.36 (1.24).

Gnathosoma - Subcapitulum (265-270 (270) long (ventral); 179-202.5 (195) long (dorsal); 93.75-105 (95) tall) colorless. Rostrum (100-102.5 (102.5) long; 37.5-38.75 (37.5) wide). Chelicerae (240-265 (265) long) with curved fangs (38-50 (50) long). Subcapitular proportions: ventral length/height 2.52-2.85 (2.84); rostrum length/width 2.65-2.73 (2.73). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (35-40 (35) long); femur (95-100 (100) long); genu (57.5-60 (57.5) long); tibia (72.5-77.5 (72.5) long; 23.75-25 (23.75) wide); tarsus (17.5-20 (17.5) long). Palpomere proportions: femur/genu 1.65-1.74 (1.74); tibia/femur 0.73-0.82 (0.73); tibia length/width 3.05-3.10 (3.05).

Venter - (590-625 (625) long; 387.5-410 (410) wide) colorless. Gnathosomal bay (112.5-127.5 (127.5) long; 72.5-78.75 (73.75) wide). Cxgl-4 subapical. Medial suture (85-107.5 (107.5) long). Genital plates (115-117.5 (116.25) long; 95-98.75 (95) wide). Additional measurements: Cx-1 (255-273 (270) long (total); 136-157 (150) long (medial)); Cx-3 (253-316 (285) wide); anterior venter (245-262.5 (262.5) long). Ventral proportions: gnathosomal bay length/width 1.55-1.73 (1.73); anterior venter/genital field length 2.12-2.26 (2.26); anterior venter length/genital field width 2.48-2.76 (2.76); anterior venter/medial suture 2.44-2.88 (2.44).

Immatures unknown.

Etymology.

Specific epithet ( walteri ) named in honor of acarologist Dave Walter for solidifying JRF’s interest in mites with his popular book on mites (Mites: Ecology, Evolution & Behaviour - Life at a Microscale) and by teaching JRF the mesostigmatan mite section of the Acarology Summer Program at The Ohio State University in 2009.

Distribution.

Probably throughout the Pacific Coastal Ranges of California, Oregon, Washington, and southern British Columbia (Figure 270). We also collected T. walteri in the Rocky Mountains of British Columbia, indicating this species might occur in the northern Rockies of Canada. However, given our sampling effort in the Rockies, we doubt the occurrence of this species in most of the US Rockies.

Remarks.

Torrenticola walteri groups with other members of the Rusetria Complex with high support and specimens are less than 2% different in COI sequence from each other. In the all analyses, T. walteri groups with the three other members of the Rusetria Complex that are found in western North America: T. mulleni , T. nortoni , and T. welbourni . These species are 5-7% different in COI sequence from each other and together make up the Western 2-Plate Identification Group. Torrenticola walteri is one of three of these that occur in California (including T. nortoni and T. welbourni ).

This species hypothesis is supported by low COI divergence within the species (0-2%) and high divergence between species (3-15%), and by the morphological characters outlined in the diagnosis.