Torrenticola shubini isher & 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 shubini isher & Dowling sp. n.

Material examined.

HOLOTYPE (♀): USA, Tennessee, Sevier County, Great Smokey Mountains National Park, middle prong Little Pigeon River (35°44'12"N, 83°24'51"W), 12 Sep 2010, by IM Smith, IMS100132.

PARATYPES (5 ♀; 5 ♂): Pennsylvania, USA: 1 ♂ (ALLOTYPE) 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, DNA 2845 • Tennessee, USA: 1 ♀ from Blount County, Great Smokey Mountains National Park, Abrams River (35°35'31"N, 83°51'21"W), 17 Sep 2010, by IM Smith, IMS100141 • 2 ♀ from Monroe County, Turkey Creek (35°21'47"N, 84°9'47"W), 12 Sep 2009, by IM Smith, IMS090112 • 1 ♂ from Sevier County, Great Smokey Mountains National Park, middle prong Little Pigeon River (35°43'33"N, 83°24'1"W), 12 Sep 2010, by IM Smith, IMS100131 • 1 ♂ from Sevier County, Great Smokey Mountains National Park, middle prong Little Pigeon River (35°44'12"N, 83°24'51"W), 12 Sep 2010, by IM Smith, IMS100132 • Vermont, USA: 2 ♀ from Addison County, Lincoln, beside Forest Service Road #54, New Haven River (44°6'N, 72°59'W), 6 Jul 1989, by IM Smith, IMS890074 • Virginia, USA: 2 ♂ from Scott County, beside Route 58/421, 0.9 kilometers east of Route 709, North Fork of Holston River (36°39'N, 82°28'W), by IM Smith, IMS900080.

Type deposition.

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

Diagnosis.

Torrenticola shubini are similar to other members of the Rusetria “4-Plates” group ( T. dunni , T. glomerabilis , T. kittatinniana , T. pollani , and T. rufoalba ) and T. skvarlai in having anterio-lateral platelets free from the dorsal plate, dorsal coloration separated into anterior and posterior portions, and indistinct hind coxal margins. Female T. shubini can be differentiated from female T. dunni by having a thinner rostrum (length/width = 2.5-2.7 in T. shubini , 2.8-3.0 in T. dunni ). Male T. dunni can be differentiated from male T. shubini by having a longer anterior venter (215-238 in T. shubini , 277-285 in T. dunni ). T. shubini can be differentiated from T. pollani by having stockier tibiae (length/width ♀ = 3.30-3.60 in T. shubini , 3.89-4.18 in T. pollani ; ♂ = 3.11-3.22 in T. shubini , 3.41-3.75 in T. pollani ) and a stockier rostrum (length/width = 2.24-2.92 in T. shubini , 3.27-3.82 in T. pollani ). T. shubini can be differentiated from T. glomerabilis by having the Dgl-4 closer to the dorsal edge (dorsal width/length between Dgl-4 = 1.2-1.4 in T. shubini ; 1.5-1.7 in T. glomerabilis ); and stockier tibiae (length/width ♀ = 3.3-3.6 in T. shubini , 4.1-4.5 in T. glomerabilis ; ♂ = 3.1-3.2 in T. shubini , 3.5-4.4 in T. glomerabilis ). Female T. shubini can be differentiated from female T. kittatinniana by having a stockier rostrum (length/width = 2.5-2.7 in T. shubini , 3.16 in T. kittatinniana ) and a taller subcapitulum (140-145 in T. shubini , 125 in T. kittatinniana ). Male T. shubini can be differentiated from male T. kittatinniana by having a shorter dorsum (400-465 in T. shubini , 500 in T. kittatinniana ) and a shorter genital field (90-108 in T. shubini , 115 in T. kittatinniana ). T. shubini can be differentiated from T. rufoalba by having a stockier rostrum (length/width = 2.24-2.92 in T. shubini , 2.96-3.06 in T. rufoalba ). Female T. shubini can be differentiated from female T. rufoalba by having a thinner genital field (137-145 in T. shubini , 157.5 in T. rufoalba ). Male T. shubini can be differentiated from male T. rufoalba by having a longer anterior venter (215-238 in T. pollani , 195 in T. rufoalba ). T. shubini can be differentiated from T. skvarlai by having a conical pedipalpal femoral tubercle, whereas T. skvarlai has a broad and flat pedipalpal femoral tubercle, and by having a longer anterior venter (♀ = 156-170 in T. shubini , 140-153 in T. skvarlai ; ♂ = 215-238 in T. shubini , 177-205 in T. skvarlai ).

Description.

Female (Figure 238) (n = 5) (holotype measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (550-640 (590) long; 415-455 (430) wide) ovoid with faint bluish-purple coloration separated into anterior and posterior portions, and with faint orange medially. Anterio-medial platelets (115-125 (122.5) long; 40-47.5 (46.25) wide). Anterio-lateral platelets (160-170 (165) long; 55-60 (56.25) wide) free from dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 310-335 (325)). Dorsal plate proportions: dorsum length/width 1.33-1.45 (1.37); dorsal width/distance between Dgl-4 1.32-1.42 (1.32); anterio-medial platelet length/width 2.63-2.88 (2.65); anterio-lateral platelet length/width 2.75-2.96 (2.93); anterio-lateral/anterio-medial length 1.28-1.43 (1.35).

Gnathosoma - Subcapitulum (300-320 (310) long (ventral); 223-255 (232) long (dorsal); 140-145 (140) tall) colorless. Rostrum (117.5-122.5 (120) long; 45-48.75 (45) wide). Chelicerae (288-320 (316) long) with curved fangs (54-63 (57) long). Subcapitular proportions: ventral length/height 2.14-2.21 (2.21); rostrum length/width 2.51-2.67 (2.67). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (42.5-47.5 (47.5) long); femur (112.5-121.25 (117.5) long); genu (63.75-70 (66.25) long); tibia (82.5-90 (83.75) long; 23.75-25 (25) wide); tarsus (17.5-17.5 (17.5) long). Palpomere proportions: femur/genu 1.71-1.83 (1.77); tibia/femur 0.68-0.75 (0.71); tibia length/width 3.30-3.60 (3.35).

Venter - (640-780 (740) long; 446-521 (447) wide) colorless. Gnathosomal bay (127.5-165 (165) long; 85-96.25 (96.25) wide). Cxgl-4 subapical. Medial suture (7.5-22.5 (7.5) long). Genital plates (156.25-175 (167.5) long; 137.5-145 wide). Additional measurements: Cx-1 (238-308 (291) long (total); 98-138 (138) long (medial)); Cx-3 (307-356 (307) wide); anterior venter (157.5-170 (157.5) long). Ventral proportions: gnathosomal bay length/width 1.50-1.94 (1.71); anterior venter/genital field length 0.94-1.05 (0.94); anterior venter length/genital field width 1.14-1.24; anterior venter/medial suture 7.50-21.00 (7.50).

Male (Figure 239) (n = 5) (allotypic measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (400-465 (460) long; 260-305 (300) wide) ovoid with faint bluish-purple coloration separated into anterior and posterior portions, and with faint orange medially. Anterio-medial platelets (82.5-100 (92.5) long; 30-40 (35) wide). Anterio-lateral platelets (115-135 (127.5) long; 35-47.5 (42.5) wide) free from dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 210-250 (250)). Dorsal plate proportions: dorsum length/width 1.52-1.57 (1.53); dorsal width/distance between Dgl-4 1.20-1.27 (1.20); anterio-medial platelet length/width 2.31-2.92 (2.64); anterio-lateral platelet length/width 2.84-3.29 (3.00); anterio-lateral/anterio-medial length 1.29-1.41 (1.38).

Gnathosoma - Subcapitulum (210-245 (240) long (ventral); 162.5-180 (171) long (dorsal); 78.75-87.5 (85) tall) colorless. Rostrum (87.5-95 (92.5) long; 30-42.5 (32.5) wide). Chelicerae (210-234 (229) long) with curved fangs (38-42.5 (40) long). Subcapitular proportions: ventral length/height 2.67-2.82 (2.82); rostrum length/width 2.24-2.92 (2.85). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (32.5-37.5 (37.5) long); femur (82.5-91.25 (87.5) long); genu (50-55 (52.5) long); tibia (62.5-72.5 (70) long; 20-22.5 (22.5) wide); tarsus (15-16.25 (15) long). Palpomere proportions: femur/genu 1.62-1.75 (1.67); tibia/femur 0.76-0.83 (0.80); tibia length/width 3.11-3.22 (3.11).

Venter - (490-571 (571) long; 310-390 (342) wide) colorless. Gnathosomal bay (92.5-115 (115) long; 55-65 (65) wide). Cxgl-4 subapical. Medial suture (95-105 (95) long). Genital plates (90-107.5 (107.5) long; 75-80 (80) wide). Additional measurements: Cx-1 (200-235 (235) long (total); 96-121 (98) long (medial)); Cx-3 (235-293 (260) wide); anterior venter (215-237.5 (232.5) long). Ventral proportions: gnathosomal bay length/width 1.54-1.82 (1.77); anterior venter/genital field length 2.16-2.39 (2.16); anterior venter length/genital field width 2.84-3.07 (2.91); anterior venter/medial suture 2.05-2.45 (2.45).

Immatures unknown.

Etymology.

Specific epithet ( shubini ) named in honor of author and palaeontologist Neil Shubin for his efforts to popularize stories of human evolution with his book (2009) and TV series (2014), Your Inner Fish. As with many of the species that Shubin studies (e.g., Tiktaalik roseae Daeschler, Shubin & Jenkins, 2006), Torrenticola shubini may represent a key evolutionary transition in the Rusetria Complex, between species that do and do not have their lateral platelets fused to the dorsal shield.

Distribution.

Appalachians (Figure 237).

Remarks.

Torrenticola shubini groups with other members of the Rusetria Complex with high support and specimens of this species are less than 2% different in COI sequence from each other. In all analyses, T. shubini groups with two other species with high support: T. dunni and T. pollani . Torrenticola shubini specimens are 5-12% different in COI sequence from these other species. The range of T. shubini overlaps with T. dunni in the southern Appalachians, but the ranges of these species do not overlap with T. pollani .

Based upon overall similarity, dorso-lateral platelet fusion, and distribution, we were able to place this species within the Eastern 4-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.