Torrenticola sellersorum 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 sellersorum Fisher & Dowling sp. n.

Material examined.

HOLOTYPE (♀): from USA, Pennsylvania, Fayette County, Ohiopyle State Park, Laurel Run (39°50'58"N, 79°30'51"W), 10 Aug 2014, by MJ Skvarla, MS 14-0810-005, DNA 2831.

PARATYPES (18 ♀; 8 ♂): Manitoba, Canada: 1 ♀ and 1 ♂ from Eating Point Creek, 0.3 kilometers east of Highway 6 (53°15'7"N, 99°18'54"W), 4 Jul 2009, by IM Smith, IMS090030A • 1 ♀ and 1 ♂ from Ochre River, beside Highway 5 (51°3'N, 99°46'W), 6 Sep 1970, by DW Barr & H Frania, ROM700638 • New Mexico, USA: 2 ♀ from Catron County, Whitewater Creek, Glenwood Whitewater Picnic Area, 5 May 2012, by IM Smith, IMS120005 • 1 ♀ from Grant County, east fork of Gila River, Grapevine Recreation Area off Route 15 north of Silver City, 5 May 2012, by IM Smith, IMS120007 • Ohio, USA: 2 ♀ and 1 ♂ from Hocking County, beside road near Ash Cave, East Branch of Queer Creek (39°24'N, 82°33'W), 5 May 1993, by IM Smith & DR Cook, IMS930001A • Pennsylvania, USA: 1 ♂ (ALLOTYPE) from Fayette County, Ohiopyle State Park, Laurel Run (39°50'58"N, 79°30'51"W), 10 Aug 2014, by MJ Skvarla, MS 14-0810-005, DNA 2835 • 1 ♂ from Fayette County, Ohiopyle State Park, Laurel Run (39°50'58"N, 79°30'51"W), 10 Aug 2014, by MJ Skvarla, MS 14-0810-005 • 2 ♀ from Westmoreland County, Irwin Park (40°19'38"N, 79°42'30"W), 4 Aug 2014, by MJ Skvarla, MS 14-0804-004 • 4 ♀ from Somerset County, Laurel Hill State Park Laurel Hill Creek (40°1'6"N, 79°14'4"W), 8 Aug 2014, by MJ Skvarla, MS 14-0808-001 • Saskatchewan, Canada: 2 ♀ and 1 ♂ from Smeaton Torch River, beside Highway 106, 26.2 km north of Highway 55, 20 Aug 2012, by IM Smith, IMS120079 • South Dakota, USA: 2 ♀ and 2 ♂ from Pennington County, Willow Creek Trail Head off Route 244, Willow Creek (43°54'N, 103°32'W), 10 Sep 1999, by IM Smith, IMS990033.

Type deposition.

Holotype (♀), allotype (♂), and other paratypes (13 ♀; 4 ♂) deposited in the CNC; other paratypes (5 ♀; 3 ♂) deposited in ACUA.

Diagnosis.

Torrenticola sellersorum 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. tysoni , T. ululata , T. whitneyae , T. microbiscutella , 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. It is one of only four Eastern 2-Plates that have dark, bold, bluish-purple coloration (also T. tysoni , T. biscutella , and T. pendula ). T. sellersorum can be differentiated from T. ululata , T. indistincta , and T. feminellai by dorsal coloration and pattern. T. sellersorum can be differentiated from T. tysoni by having a stockier rostrum (length/width ♀ = 2.44-2.68 in T. sellersorum , 3.06-3.31 in T. tysoni ; ♂ = 2.71-3.05 in T. sellersorum , 3.14-3.50 in T. tysoni ). Female T. sellersorum can be differentiated from female T. biscutella by anterior venter/genital field length (0.69-0.77 in T. sellersorum , 0.82-0.88 in T. biscutella ). Male T. sellersorum can be differentiated from male T. biscutella by having slightly more elongate anterio-lateral platelets (length/width = 2.76-3.00 in T. sellersorum , 2.58-2.74 in T. biscutella ). T. sellersorum can be differentiated from T. pendula by having a stockier gnathosomal bay (length/width = 1.56-2.08 in T. sellersorum , 2.42-2.90 in T. pendula ) and more elongate tibiae (length/width = 3.13-3.8 in T. sellersorum , 2.78-3.05 in T. pendula ). T. sellersorum can be differentiated from T. whitneyae by having more elongate pedipalpal tibiae (length/width = 3.13-3.80 in T. sellersorum , 2.42-2.95 in T. whitneyae ). T. sellersorum can be differentiated from T. microbiscutella by having a less elongate dorsum (length/width = 1.23-1.54 in T. sellersorum , 1.63-1.75 in T. microbiscutella ). Female T. sellersorum can be differentiated from female T. malarkeyorum by anterior venter/genital field length (0.69-0.77 in T. sellersorum , 0.85-0.89 in T. malarkeyorum ). Female T. sellersorum can be differentiated from female T. caerulea by having a wider genital field (150-182 in T. sellersorum , 120-145 in T. caerulea ). Female T. sellersorum can be differentiated from female T. delicatexa by having a rounder dorsum (length/width = 1.23-1.37 in T. sellersorum , 1.38-1.44 in T. delicatexa ). Male T. sellersorum do not have any measurement differences with male T. malarkeyorum , T. caerulea , and T. delicatexa ; however, they can be differentiated by dorsal coloration.

Description.

Female (Figure 232) (n = 5) (holotype measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (540-650 (540) long; 400-520 (400) wide) ovoid with bold (occasionally faint) bluish-purple coloration separated into anterior and posterior portions with a thin or thick strip of red medially. Anterio-medial platelets (112.5-135 (117.5) long; 35-50 (35) wide). Anterio-lateral platelets (147.5-172.5 (147.5) long; 47.5-75 (47.5) wide) fused to dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 290-370 (295)). Dorsal plate proportions: dorsum length/width 1.23-1.37 (1.35); dorsal width/distance between Dgl-4 1.35-1.42 (1.36); anterio-medial platelet length/width 2.65-3.36 (3.36); anterio-lateral platelet length/width 2.23-3.11 (3.11); anterio-lateral/anterio-medial length 1.26-1.36 (1.26).

Gnathosoma - Subcapitulum (282.5-330 (285) long (ventral); 210-245 (219) long (dorsal); 130-157.5 (135) tall) colorless. Rostrum (110-125 (113.75) long; 42.5-47.5 (42.5) wide). Chelicerae 280-325 (280) long) with curved fangs (51-66 (62) long). Subcapitular proportions: ventral length/height 2.05-2.17 (2.11); rostrum length/width 2.44-2.68 (2.68). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (40-50 (42.5) long); femur (107.5-122.5 (110) long); genu (62.5-72.5 (65) long); tibia (82.5-95 (85) long; 22.5-27.5 (22.5) wide); tarsus (17.5-20 (20) long). Palpomere proportions: femur/genu 1.69-1.85 (1.69); tibia/femur 0.75-0.79 (0.77); tibia length/width 3.14-3.80 (3.78).

Venter - (640-800 (645) long; 449-529 (470) wide) colorless. Gnathosomal bay (132.5-187.5 (157.5) long; 82.5-97.5 (82.5) wide). Cxgl-4 subapical. Medial suture (0-10 (0) long) often absent. Genital plates (160-195 (165) long; 150-181.25 (157.5) wide). Additional measurements: Cx-1 (230-322 (270) long (total); 83-126 (106) long (medial)); Cx-3 (310-365 (319) wide); anterior venter (120-142.5 (120) long). Ventral proportions: gnathosomal bay length/width 1.56-2.08 (1.91); anterior venter/genital field length 0.69-0.77 (0.73); anterior venter length/genital field width 0.74-0.80 (0.76); anterior venter/medial suture (proportion cannot be calculated for specimens without a medial suture) 12.25-17.00.

Male (Figure 233) (n = 5) (allotypic measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (390-470 (400) long; 255-330 (280) wide) ovoid with bold (occasionally faint) bluish-purple coloration separated into anterior and posterior portions with a thin or thick strip of red medially. Anterio-medial platelets (82.5-97.5 (82.5) long; 30-40 (30) wide). Anterio-lateral platelets (112.5-145 (120) long; 37.5-52.5 (42.5) wide) fused to dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 190-250 (220)). Dorsal plate proportions: dorsum length/width 1.42-1.54 (1.43); dorsal width/distance between Dgl-4 1.27-1.34 (1.27); anterio-medial platelet length/width 2.44-2.83 (2.75); anterio-lateral platelet length/width 2.76-3.00 (2.82); anterio-lateral/anterio-medial length 1.32-1.49 (1.45).

Gnathosoma - Subcapitulum (205-245 (215) long (ventral); 151-179 (166) long (dorsal); 80-107.5 (91.25) tall) colorless. Rostrum 80-95 (85) long; 27.5-35 (30) wide). Chelicerae (195-235 (208) long) with curved fangs (40-50 (46) long). Subcapitular proportions: ventral length/height 2.24-2.59 (2.36); rostrum length/width 2.71-3.05 (2.83). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (30-38.75 (30) long); femur (75-87.5 (80) long); genu (46.25-52.5 (50) long); tibia (62.5-70 (67.5) long; 18.75-21.25 (20) wide); tarsus (15-17.5 (15) long). Palpomere proportions: femur/genu 1.60-1.67 (1.60); tibia/femur 0.79-0.87 (0.84); tibia length/width 3.13-3.47 (3.38).

Venter - (465-570 (490) long; 290-367 (325) wide) colorless. Gnathosomal bay (105-135 (117.5) long; 57.5-66.25 (65) wide). Cxgl-4 subapical. Medial suture (57.5-72.5 (57.5) long). Genital plates (102.5-122.5 (107.5) long; 91.25-115 (96.25) wide). Additional measurements: Cx-1 (189-237 (199) long (total); 79-96 (85) long (medial)); Cx-3 (230-290 (232) wide); anterior venter (150-185 (150) long). Ventral proportions: gnathosomal bay length/width 1.75-2.08 (1.81); anterior venter/genital field length 1.39-1.59 (1.40); anterior venter length/genital field width 1.55-1.78 (1.56); anterior venter/medial suture 2.32-2.61 (2.61).

Immatures unknown.

Etymology.

Specific epithet ( sellersorum ) named in honor of the grandparents of DMF, who always supported and encouraged her love of nature and discovery.

Distribution.

Widespread (Figure 231). T. sellersorum are unlike all other Torrenticola in our collections in that they span either side of the Great Plains, which act as a barrier for most other species. T. sellersorum are likely absent from cool, highland streams of the Appalachians, Interior Highlands, and Rocky Mountains, but are likely widely distributed throughout the Interior. Explaining the peculiar distribution of T. sellersorum will depend on knowledge of dispersal capabilities, including host preference by the larvae and the dispersal capabilities of the host.

Remarks.

In all analyses, Torrenticola sellersorum groups with other members of the Rusetria Complex with high support and specimens of this species are less than 2.3% different in COI sequence from each other. In all analysis, T. sellersorum groups with other eastern members of the Rusetria Complex that have fused lateral platelets. Because of this, we are able to place this species in the Eastern 2-Plate Identification Group.

The slightly increased COI variation of this species (2.3%) is expected for specimens separated by great geographic distance. For example, the specimens from Pennsylvania are 0-1.3% different from each other and the specimens from Saskatchewan are 0.3% different from each other, but Pennsylvania specimens are 1.3-2.0% different from the Saskatchewan specimens. However, even specimens from New Mexico are only 2.0-2.3% different from other localities, despite being separated by great geographic distance and ecoregions that act as barriers for other Torrenticola (i.e., the Great Plains). This variation in COI in the New Mexico samples supports two hypotheses: 1) given the relatively low divergence of approximately 2%, New Mexico specimens represent the same species as specimens further east; and conversely, 2) given the relatively high divergence of greater than 1%, New Mexico specimens represent a long-standing population, not a recent introduction from the east.

This species hypothesis is supported by low COI divergence within the species (0-2.3%) (but see above discussion) and high divergence between species (3-15%), and by the morphological characters outlined in the diagnosis.