Torrenticola unimaculata 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 unimaculata Fisher & Dowling sp. n.

Material examined.

HOLOTYPE (♀): from Canada, New Brunswick, York County, SW Mirimachi River, beside Highway 107 between Napdogan and Juniper, 21 Jun 2012, by IM Smith, IMS120036, DNA 3010.

PARATYPES (7 ♀; 7 ♂): Arkansas, USA: 2 ♀ and 1 ♂ from Montgomery County, Caddo Gap, access track off Manfred Road, 0.3 km west of Route 8, 29 Jul 2011, by IM Smith, IMS110037 • 4 ♀ from Montgomery County, Gaston, South Fork of Ouachita River, access off County Road 17 at Forest Road 903, 29 Jul 2011, by IM Smith, IMS110040 • 2 ♂ from Montgomery County, Ouachita River, Pine Ridge, 5 Oct 2007, by AJ Radwell, & HW Robison, AJR070300A • 2 ♂ from Montgomery County, Ouachita National Forest, South Fork of Ouachita River, 29 Jul 2011, by AJ Radwell, & B Crump, AJR110302 • New Brunswick, Canada: 1 ♂ (ALLOTYPE) from York County, SW Mirimachi River, beside Highway 107 between Napdogan and Juniper, 21 Jun 2012, by IM Smith, IMS120036, DNA 3011 • 1 ♀ and 1 ♂ from York County, SW Mirimachi River, beside Highway 107 between Napdogan and Juniper, 21 Jun 2012, by IM Smith, IMS120036.

Type deposition.

Holotype (♀), allotype (♂), and most paratypes (4 ♀; 3 ♂) deposited in the CNC; other paratypes (3 ♀; 3 ♂) deposited in ACUA.

Diagnosis.

Torrenticola unimaculata are similar to other members of the Tricolor Complex ( T. bittikoferae , T. hoosieri , T. larvata , T. pearsoni , T. olliei , T. sierrensis , T. tricolor , T. trimaculata , T. cardia , T. kringi , T. dimorpha , and T. mohawk ) in having a short, conical rostrum. T. unimaculata can be differentiated from most Torrenticola , including other members of the Tricolor Complex, by having a distinct dorsal pattern of a large anterior dorsal spot. The only other species with this pattern is T. ululata , which, like all Rusetria 2-Plates, have anterio-lateral platelets fused to the dorsal plate and T. kringi , which has a more elongate rostrum (length/width = 1.9-2.2 in T. unimaculata , 2.6-3.2 in T. kringi ). T. unimaculata are most similar to other members of the Tricolor Complex that have bold patterning ( T. larvata , T. tricolor , T. trimaculata , T. cardia , T. kringi , and T. mohawk ). Female T. unimaculata can be further differentiated from these members of the complex by having a longer medial suture (♀ = 40-47.5 in T. unimaculata , 15-35 in others), except T. cardia (25-50) and T. mohawk (30-45).

Description.

Female (Figure 265) (n = 6) (holotype measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (650-730 (720) long; 490-600 (600) wide) ovoid with coloration restricted to a single dark spot anteriorly (occasionally extending medially), with an orange spot posterior to the dark spot. Anterio-medial platelets (127.5-145 (140) long; 62.5-70 (67.5) wide). Anterio-lateral platelets (172.5-200 (200) long; 72.5-80 (80) wide) free from dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 350-425 (425)). Dorsal plate proportions: dorsum length/width 1.20-1.39 (1.20); dorsal width/distance between Dgl-4 1.34-1.41 (1.41); anterio-medial platelet length/width 1.89-2.08 (2.07); anterio-lateral platelet length/width 2.29-2.57 (2.50); anterio-lateral/anterio-medial length 1.35-1.44 (1.43).

Gnathosoma - Subcapitulum (242.5-265 (265) long (ventral); 176.25-194 (190) long (dorsal); 110-125 (125) tall) colorless. Rostrum (85-100 (92.5) long; 42.5-47.5 (47.5) wide) short and conical. Chelicerae (236-252 (250) long) with curved fangs (51-61.5 (55) long). Subcapitular proportions: ventral length/height 2.12-2.26 (2.12); rostrum length/width 1.89-2.18 (1.95). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (35-42.5 (42.5) long); femur (91.25-100 (100) long); genu (62.5-67.5 (67.5) long); tibia (80-87.5 (87.5) long; 25-26.25 (26.25) wide); tarsus (20-25 (22.5) long). Palpomere proportions: femur/genu 1.46-1.52 (1.48); tibia/femur 0.81-0.93 (0.88); tibia length/width 3.20-3.40 (3.33).

Venter - (700-860 (860) long; 539-630 (630) wide) colorless. Gnathosomal bay (110-140 (140) long; 75-87.5 (80) wide). Cxgl-4 subapical. Medial suture (40-47.5 (40) long). Genital plates (180-210 (210) long; 152.5-170 (170) wide). Additional measurements: Cx-1 (243-290 (290) long (total); 128-162 (145) long (medial)); Cx-3 (358-426 (390) wide); anterior venter (182.5-205 (195) long). Ventral proportions: gnathosomal bay length/width 1.40-1.75 (1.75); anterior venter/genital field length 0.93-1.14 (0.93); anterior venter length/genital field width 1.15-1.30 (1.15); anterior venter/medial suture 4.06-4.88 (4.88).

Male (Figure 266) (n = 6) (allotypic measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum- (525-690 (690) long; 400-520 (520) wide) ovoid with coloration restricted to a single dark spot anteriorly (occasionally extending medially), with an orange spot posterior to the dark spot. Anterio-medial platelets (112.5-137.5 (137.5) long; 57.5-72.5 (72.5) wide). Anterio-lateral platelets (160-205 (205) long; 65-82.5 (82.5) wide) free from dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 320-405 (405)). Dorsal plate proportions: dorsum length/width 1.30-1.43 (1.33); dorsal width/distance between Dgl-4 1.23-1.28 (1.28); anterio-medial platelet length/width 1.90-2.09 (1.90); anterio-lateral platelet length/width 2.28-2.54 (2.48); anterio-lateral/anterio-medial length 1.35-1.43 (1.33).

Gnathosoma - Subcapitulum (212.5-255 (255) long (ventral); 155-185 (185) long (dorsal); 90-110 (110) tall) colorless. Rostrum (80-95 (95) long; 37.5-48.75 (48.75) wide) short and conical. Chelicerae (195-235 (235) long) with curved fangs (42-55 (55) long). Subcapitular proportions: ventral length/height 2.32-2.42 (2.32); rostrum length/width 1.95-2.2 (1.95). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (32.5-40 (40) long); femur (80-97.5 (97.5) long); genu (55-67.5 (67.5) long); tibia (70-80 (80) long; 22.5-27.5 (27.5) wide); tarsus (20-22.5 (22.5) long). Palpomere proportions: femur/genu 1.39-1.48 (1.44); tibia/femur 0.82-0.91 (0.82); tibia length/width 2.90-3.11 (2.91).

Venter - (640-800 (800) long; 448-570 (570) wide) colorless. Gnathosomal bay (97.5-132.5 (132.5) long; 62.5-77.5 (72.5) wide). Cxgl-4 subapical. Medial suture (107.5-125 (125) long). Genital plates (130-161.25 (161.25) long; 92.5-112.5 (112.5) wide). Additional measurements: Cx-1 (218-338 (290) long (total); 109-165 (165) long (medial)); Cx-3 (218-338 (290) wide); anterior venter (265-300 (300) long). Ventral proportions: gnathosomal bay length/width 1.44-1.83 (1.83); anterior venter/genital field length 1.86-2.13 (1.86); anterior venter length/genital field width 2.67-2.92 (2.67); anterior venter/medial suture 2.30-2.49 (2.40).

Immatures unknown.

Etymology.

Specific epithet ( unimaculata ) named for the single dark dorsal spot of this species (unus, L. one; macula, L. spot).

Distribution.

Known only from Arkansas and New Brunswick (Figure 264).

Remarks.

Torrenticola unimaculata groups with other members of the Tricolor Complex with high support and specimens of this species are less than 2% different in COI sequence from each other. In all analyses, T. unimaculata groups with two other species which also have dorsal spots: T. trimaculata and T. tricolor . This clade represents some of the most distinctive of all Torrenticola . This species is greater than 7% different in COI from sister species.

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