Torrenticola tysoni 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 tysoni Fisher & Dowling sp. n.

Material examined.

HOLOTYPE (♀): from USA, Alabama, Lauderdale County, off Natchez Trace Parkway, 7 km south of Tennessee state line (34°56'31"N, 87°49'41"W), 24 Sep 2009, by IM Smith, IMS090121, DNA 2871.

PARATYPES (6 ♀; 5 ♂): Alabama, USA: 1 ♂ (ALLOTYPE) from Lauderdale County, off Natchez Trace Parkway, 7 km south of Tennessee state line (34°56'31"N, 87°49'41"W), 24 Sep 2009, by IM Smith, IMS090121, DNA 2870 • 1 ♀ from Lauderdale County, off Natchez Trace Parkway, 7 km south of Tennessee state line (34°56'31"N, 87°49'41"W), 24 Sep 2009, by IM Smith, IMS090121 • 2 ♀ and 2 ♂ from Lauderdale County, off Natchez Trace Parkway, 7 km south of Tennessee state line (34°56'32"N, 87°49'43"W), 27 Sep 2010, by IM Smith, IMS100163 • 1 ♂ from Lauderdale County, off Natchez Trace Parkway, 7 km south of Tennessee state line (34°56'31"N, 87°49'41"W), 27 Sep 2010, by IM Smith, IMS100162 • Tennessee, USA: 3 ♀ and 1 ♂ from Wayne County, Glenrock Branch Creek (35°15'50"N, 87°37'34"W), 24 Sep 2009, by IM Smith, IMS090124.

Type deposition.

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

Diagnosis.

Torrenticola tysoni 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. 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. biscutella , T. sellersorum , and T. pendula ). T. tysoni can be further differentiated from other Eastern 2-Plates by having a more elongate rostrum (length/width = ♀ = 3.06-3.31 in T. tysoni , 2.33-3.0 in others; ♂ = 3.14-3.50 in T. tysoni , 2.50-3.05 in others), except T. feminellai (3.05-3.38) and female T. pendula (3.0-3.06). T. tysoni can be differentiated from T. feminellai and T. pendula by dorsal coloration and pattern.

Description.

Female (Figure 259) (n = 5) (holotype measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (610-670 (670) long; 450-475 (475) wide) ovoid with bold bluish-purple coloration separated into anterior and posterior portions, and with faint orange medially. Anterio-medial platelets (125-137.5 (135) long; 42.5-52.5 (52.5) wide). Anterio-lateral platelets (162.5-175 (172.5) long; 55-67.5 (67.5) wide) fused to dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 320-330 (330)). Dorsal plate proportions: dorsum length/width 1.35-1.41 (1.41); dorsal width/distance between Dgl-4 1.38-1.44 (1.44); anterio-medial platelet length/width 2.50-3.18 (2.57); anterio-lateral platelet length/width 2.56-3.18 (2.56); anterio-lateral/anterio-medial length 1.18-1.40 (1.28).

Gnathosoma - Subcapitulum (310-327.5 (327.5) long (ventral); 230-245 (245) long (dorsal); 130-135 (135) tall) mostly colorless. Rostrum (125-132.5 (130) long; 40-42.5 (42.5) wide). Chelicerae (315-380 (350) long) with curved fangs (57.5-60 (60) long). Subcapitular proportions: ventral length/height 2.30-2.46 (2.43); rostrum length/width 3.06-3.31 (3.06). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (37.5-47.5 (45) long); femur (112.5-120 (120) long); genu (62.5-70 (70) long); tibia (80-90 (87.5) long; 22.5-25 (25) wide); tarsus (17.5-22.5 (20) long). Palpomere proportions: femur/genu 1.61-1.80 (1.71); tibia/femur 0.70-0.80 (0.73); tibia length/width 3.50-3.67 (3.50).

Venter - (715-790 (790) long; 505-560 (540) wide) with bold bluish-purple coloration. Gnathosomal bay (162.5-172.5 (172.5) long; 72.5-100 (85) wide). Cxgl-4 subapical. Medial suture (13.75-22.5 (22.5) long). Genital plates (175-185 (180) long; 152.5-155 (155) wide). Additional measurements: Cx-1 (280-315 (310) long (total); 115-145 (140) long (medial)); Cx-3 (310-350 (335) wide); anterior venter (150-172.5 (172.5) long). Ventral proportions: gnathosomal bay length/width 1.65-2.24 (2.03); anterior venter/genital field length 0.81-0.99 (0.96); anterior venter length/genital field width 0.97-1.11 (1.11); anterior venter/medial suture 7.67-11.27 (7.67).

Male (Figure 260) (n = 5) (allotypic measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (430-485 (460) long; 310-340 (320) wide) ovoid with bold bluish-purple coloration separated into anterior and posterior portions, and with faint orange medially. Anterio-medial platelets (97.5-127.5 (127.5) long; 35-40 (40) wide). Anterio-lateral platelets (127.5-137.5 (127.5) long; 42.5-50 (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-4 235-245 (240)). Dorsal plate proportions: dorsum length/width 1.39-1.48 (1.44); dorsal width/distance between Dgl-4 1.32-1.39 (1.33); anterio-medial platelet length/width 2.60-3.19 (3.19); anterio-lateral platelet length/width 2.65-3.00 (2.68); anterio-lateral/anterio-medial length 1.00-1.31 (1.00).

Gnathosoma - Subcapitulum (250-265 (250) long (ventral); 192.5-200 (195) long (dorsal); 77.5-95 (90) tall) mostly colorless. Rostrum (100-110 (100) long; 30-35 (30) wide). Chelicerae (237.5-260 (250) long) with curved fangs (45-47.5 (45) long). Subcapitular proportions: ventral length/height 2.76-3.23 (2.78); rostrum length/width 3.14-3.50 (3.33). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (33.75-48.75 (37.5) long); femur (87.5-97.5 (92.5) long); genu (52.5-62.5 (57.5) long); tibia (67.5-75 (75) long; 20-21.25 (21.25) wide); tarsus (15-17.5 (15) long). Palpomere proportions: femur/genu 1.56-1.68 (1.61); tibia/femur 0.72-0.81 (0.81); tibia length/width 3.18-3.63 (3.53).

Venter- (540-585 (560) long; 350-410 (360) wide) with bold bluish-purple coloration. Gnathosomal bay (110-122.5 (112.5) long; 62.5-67.5 (62.5) wide). Cxgl-4 subapical. Medial suture (85-115 (85) long). Genital plates (110-117.5 (110) long; 87.5-92.5 (92.5) wide). Additional measurements: Cx-1 (240-250 (240) long (total); 115-127.5 (122.5) long (medial)); Cx-3 (250-290 (265) wide); anterior venter (227.5-250 (232.5) long). Ventral proportions: gnathosomal bay length/width 1.69-1.85 (1.80); anterior venter/genital field length 1.98-2.13 (2.11); anterior venter length/genital field width 2.51-2.86 (2.51); anterior venter/medial suture 2.17-2.74 (2.74).

Immatures unknown.

Etymology.

Specific epithet ( tysoni ) named in honor of Neil Degrasse Tyson for his efforts in popularizing cosmology and science in general with Cosmos: A Spacetime Odyssey (2014), which was a worthy update to Carl Sagan’s Cosmos: A Personal Voyage (1980).

Distribution.

Known only from several localities along Natchez Trace Parkway (Figure 258).

Remarks.

Torrenticola tysoni groups with other members of the Rusetria Complex with high support. Specimens of this species from Tennessee and Alabama are less than 1% different in COI sequence from each other and the specimen from Arkansas is less than 2% different from those. This species is greater than 10% different from sister species.

In all analyses, T. tysoni groups with two other species ( T. sellersorum and T. pendula ) as a paraphyletic grade at the base of the Eastern 2-Plate Identification Group. Based upon overall similarity, lateral platelets fused with the dorsal shield, and distribution, we were able to place this species within the Eastern 2-Plate Identification Group.

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.