Torrenticola microbiscutella 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 microbiscutella Fisher & Dowling sp. n.

Material examined.

HOLOTYPE (♀): from USA, Georgia, White County, Helen; beside Road to Anna Ruby Falls just north of Unicoi State Park, (34°44'44"N, 83°43'43"W), 24 September 1992, by IM Smith, IMS920051.

PARATYPES (5 ♀; 6 ♂): Georgia, USA: 1 ♂ (ALLOTYPE) from White County, Helen; beside Road to Anna Ruby Falls just north of Unicoi State Park, (34°44'44"N, 83°43'43"W), 24 September 1992, by IM Smith, IMS920051 • 3 ♀ and 4 ♂ from White County, Helen; beside Road to Anna Ruby Falls just north of Unicoi State Park, (34°44'44"N, 83°43'43"W), 24 September 1992, by IM Smith, IMS920051 • North Carolina, USA: • 2 ♀ and 2 ♂ from Macon County, Rainbow Springs; beside Forest Route 67, 2.0 km south of road to Standing Indian Campground, (35°3'3"N, 83°31'31"W), 1 July 1990, by IM Smith, IMS900072.

Type deposition.

Holotype (♀), allotype (♂), and some paratypes (3 ♀; 3 ♂) deposited in the CNC; other paratypes (2 ♀; 2 ♂) deposited in the ACUA.

Diagnosis.

Torrenticola microbiscutella are similar to other members of the Rusetria "Eastern 2-Plates" group ( T. biscutella , T. caerulea , T. delicatexa , T. indistincta , T. malarkeyorum , T. pendula , T. sellersorum , T. tysoni , T. ululata , T. whitneyae , and T. feminellai ) in having anterio-lateral platelets fused to the dorsal plate, having dorsal coloration separated into anterior and posterior portions (except T. ululata and T. indistincta ), and being distributed in the east. T. microbiscutella can be differentiated from all other Eastern 2-Plates by having an elongate dorsum (length/width = 1.63-1.75 in T. microbiscutella , 1.21-1.56 in others). T. microbiscutella can be differentiated from most other Eastern 2-Plates by having faint dorsal coloration (most other Eastern 2-Plates have bold coloration).

Description.

Female (Figure 144) (n = 5) (holotype measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (490-540 (510) long; 290-325 (300) wide) ovoid and elongate with faint reddish-purple coloration separated into anterior and posterior portions. Anterio-medial platelets (105-112.5 (110) long; 32.5-36.25 (33.75) wide). Anterio-lateral platelets (130-147.5 (135) long; 35-45 (45) wide) fused to dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 235-250 (235)). Dorsal plate proportions: dorsum length/width 1.65-1.75 (1.70); dorsal width/distance between Dgl-4 1.23-1.30 (1.28); anterio-medial platelet length/width 3.00-3.46 (3.26); anterio-lateral platelet length/width 3.00-3.79 (3.00); anterio-lateral/anterio-medial length 1.20-1.34 (1.23).

Gnathosoma - Subcapitulum (260-270 (270) long (ventral); 195-210 (210) long (dorsal); 105-110 (107.5) tall) colorless. Rostrum (102.5-107.5 (107.5) long; 40-42.5 (42.5) wide) conical. Chelicerae (255-265 (262.5) long) with curved fangs (55-55 (55) long). Subcapitular proportions: ventral length/height 2.45-2.57 (2.51); rostrum length/width 2.53-2.63 (2.53). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (35-37.5 (37.5) long); femur (92.5-97.5 (97.5) long); genu (55-60 (57.5) long); tibia (72.5-80 (75) long; 20-22.5 (21.25) wide); tarsus (15-17.5 (17.5) long). Palpomere proportions: femur/genu 1.57-1.70 (1.70); tibia/femur 0.77-0.84 (0.77); tibia length/width 3.53-3.65 (3.53).

Venter - (610-660 (620) long; 335-370 (370) wide) colorless. Gnathosomal bay (120-142.5 (120) long; 65-75 (75) wide). Cxgl-4 subapical. Medial suture (42.5-50 (45) long). Genital plates (135-150 (145) long; 117.5-125 (120) wide). Additional measurements: Cx-1 (220-240 (230) long (total); 95-105 (105) long (medial)); Cx-3 (235-270 (270) wide); anterior venter (150-160 (157.5) long). Ventral proportions: gnathosomal bay length/width 1.60-2.04 (1.60); anterior venter/genital field length 1.07-1.15 (1.09); anterior venter length/genital field width 1.25-1.33 (1.31); anterior venter/medial suture 3.10-3.76 (3.50).

Male (Figure 145) (n = 5) (allotypic measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (430-455 (440) long; 260-280 (260) wide) ovoid and elongate with faint reddish-purple coloration separated into anterior and posterior portions. Anterio-medial platelets (82.5-101.25 (95) long; 31.25-35 (35) wide). Anterio-lateral platelets (115-127.5 (115) long; 35-40 (37.5) wide) fused to dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 205-215 (205)). Dorsal plate proportions: dorsum length/width 1.63-1.69 (1.69); dorsal width/distance between Dgl-4 1.21-1.30 (1.27); anterio-medial platelet length/width 2.64-3.12 (2.71); anterio-lateral platelet length/width 3.07-3.64 (3.07); anterio-lateral/anterio-medial length 1.21-1.45 (1.21).

Gnathosoma - Subcapitulum (215-235 (232.5) long (ventral); 162.5-177.5 (176.25) long (dorsal); 77.5-90 (87.5) tall) colorless. Rostrum (82.5-95 (92.5) long; 30-36.25 (35) wide) conical. Chelicerae (197.5-232.5 (212.5) long) with curved fangs (45-47.5 (47.5) long). Subcapitular proportions: ventral length/height 2.58-2.77 (2.66); rostrum length/width 2.62-2.85 (2.64). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (30-32.5 (32.5) long); femur (75-81.25 (76.25) long); genu (50-53.75 (50) long); tibia (66.25-70 (67.5) long; 18.75-20 (20) wide); tarsus (15-17.5 (15) long). Palpomere proportions: femur/genu 1.50-1.60 (1.53); tibia/femur 0.84-0.90 (0.89); tibia length/width 3.31-3.60 (3.38).

Venter - (530-575 (540) long; 270-310 (305) colorless. Gnathosomal bay (110-125 (110) long; 55-60 (60) wide). Cxgl-4 subapical. Medial suture (75-90 (90) long). Genital plates (85-95 (90) long; 85-100 (85) wide). Additional measurements: Cx-1 (200-220 (205) long (total); 95-100 (100) long (medial)); Cx-3 (220-240 (240) wide); anterior venter (185-195 (195) long). Ventral proportions: gnathosomal bay length/width 1.83-2.18 (1.83); anterior venter/genital field length 2.00-2.29 (2.17); anterior venter length/genital field width 1.95-2.29 (2.29); anterior venter/medial suture 2.17-2.47 (2.17).

Immatures unknown.

Etymology.

Specific epithet ( microbiscutella ) is named because this species is the smallest (at least in females) and most elongate of all members of the Rusetria Complex ( mikrós, G. small; bi, L. two; scutella, L. little plate).

Distribution.

Southern Appalachians (Figure 143).

Remarks.

Unfortunately, we were unable to acquire fresh material of Torrenticola microbiscutella and therefore this species is not included in our phylogenetic analyses. However, we were able to examine morphology with material preserved in GAW. The overall similarity, distribution in the east, and fusion of the dorso-lateral platelets to the dorsal plate, are consistent with placing this species in the Rusetria Complex and Eastern 2-Plate Identification Group.