Torrenticola gnoma 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 gnoma Fisher & Dowling sp. n.

Material examined.

HOLOTYPE (♀): from USA, Mississippi, Attala County, Hurricane Creek (33°4'57"N, 89°31'29"W), 12 Sep 2008, by IM Smith, IMS080052.

PARATYPES (6 ♀; 10 ♂): Georgia, USA: 1 ♂ from Lowndes County, Withlacoochee River, beside Route 84 at Brooks County line, 13 Sep 1968, by DR Cook, DRC680075 • Illinois, USA: 1 ♀ and 2 ♂ from Clark County, Big Creek (32°25'59"N, 87°41'15"W), 30 Jul 2014, by MJ Skvarla, MS 14-0730-001 • 1 ♂ from Vermilion County, Fairmount, beside Vermilion County Road 680E, Jordan Creek (40°4'N, 87°50'W), 10 Sep 1991, by IM Smith, IMS910030 • Mississippi, USA: 1 ♂ (ALLOTYPE) from USA, Mississippi, Attala County, Hurricane Creek (33°4'57"N, 89°31'29"W), 12 Sep 2008, by IM Smith, IMS080052 • 1 ♀ and 1 ♂ from Attala County, Hurricane Creek (33°4'58"N, 89°31'31"W), 30 Sep 2010, by IM Smith, IMS100168 • 1 ♀ and 1 ♂ from Grenada County, Leflore, beside Black Creek Road, Black Creek (33°43'N, 90°3'W), 16 Sep 1991, by IM Smith, IMS910044 • 1 ♀ and 1 ♂ from Jefferson County, off Natchez Trace Parkway, Coles Creek (31°41'26"N, 91°10'52"W), 2 Oct 1994, by IM Smith, IMS940029A • 1 ♀ and 1 ♂ from Tishomingo County, Tishomingo State Park, Bear Creek, (34°36'N, 88°11'W), 18 Sep 1991, by IM Smith, IMS910047A • Oklahoma, USA: 2 ♀ and 2 ♂ from Pushmataha County, beside Route 271, South of Albion, Walnut Creek (34°39'N, 95°7'W), 1 Jul 1987, by IM Smith, IMS870063A.

Type deposition.

Holotype (♀), allotype (♂), and some paratypes (4 ♀; 5 ♂) deposited in the CNC; other paratypes (2 ♀; 3 ♂) deposited in ACUA.

Diagnosis.

Torrenticola gnoma are similar to other members of the Raptor Group ( T. irapalpa , T. longitibia , T. mjolniri , T. elusiva , T. racupalpa , T. raptor , T. danielleae , T. daemon , and T. ivyae ) in having round bodies; Dgl-4 close to muscles scars; long, thin subcapitular rostra; and long, thin pedipalp tibiae. T. gnoma can be differentiated from T. elusiva by being smaller (dorsum length = 540-595 in T. gnoma , 645 in T. elusiva ); having a stockier rostrum (length/width = 2.74-3.13 in T. gnoma , 3.65 in T. elusiva ); and by dorsal coloration. T. gnoma can be differentiated from T. racupalpa by having a stockier rostrum (length/width = 2.74-3.13 in T. gnoma , 3.56-3.88 in T. racupalpa ) and by dorsal coloration and pattern. T. gnoma can be differentiated from T. irapalpa , T. danielleae , and T. daemon by dorsal coloration and pattern. Additionally, female T. gnoma can be differentiated from female T. irapalpa , T. danielleae , and T. daemon by having Dgl-4 closer to the muscle scars (dorsal width/distance between Dgl-4 ♀ = 2.65-3.29 in T. gnoma , 1.57-2.09 in others). T. gnoma can be differentiated from T. mjolniri , T. longitibia , T. raptor , and T. ivyae by having stockier pedipalp tibiae (length/width = 3.88-4.67 in T. gnoma , 4.75-7.54 in others) and a stockier rostrum (length/width = 2.56-3.23 in T. gnoma , 3.44-4.4 in others).

Description.

Female (Figure 88) (n = 5) (holotype measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (540-595 (550) long; 440-500 (455) wide) circular with a large spot of coloration medially extending in a thin strip anteriorly to the edge of the dorsal plate, coloration variable from navy blue to purple to pink. Anterio-medial platelets (122.5-137.5 (131.25) long; 55-62.5 (60) wide). Anterio-lateral platelets (152.5-187.5 (167.5) long; 67.5-75 (70) wide) free from dorsal plate. Dgl-4 much closer to the muscle scar than to dorsum edge (distance between Dgl-4 140-185 (155)). Dorsal plate proportions: dorsum length/width 1.17-1.30 (1.21); dorsal width/distance between Dgl-4 2.65-3.29 (2.94); anterio-medial platelet length/width 2.06-2.39 (2.19); anterio-lateral platelet length/width 2.26-2.59 (2.39); anterio-lateral/anterio-medial length 1.11-1.46 (1.28).

Gnathosoma - Subcapitulum (285-305 (290) long (ventral); 225-239 (226) long (dorsal); 115-135 (120) tall) colorless. Rostrum (122.5-130 (125) long; 40-47.5 (40) wide) elongate. Chelicerae (285-310 (286) long) with curved fangs (53-60 (54) long). Subcapitular proportions: ventral length/height 2.26-2.52 (2.42); rostrum length/width 2.74-3.13 (3.13). Pedipalps elongate with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (40-45 (40) long); femur (110-120 (112.5) long); genu (60-67.5 (62.5) long); tibia (87.5-105 (92.5) long; 20-22.5 (20) wide); tarsus (17.5-20 (17.5) long). Palpomere proportions: femur/genu 1.63-1.88 (1.80); tibia/femur 0.76-0.88 (0.82); tibia length/width 4.17-4.67 (4.63).

Venter - (660-730 (680) long; 500-575 (500) wide) colorless. Gnathosomal bay (142.5-172.5 (152.5) long; 75-92.5 (75) wide). Cxgl-4 subapical. Medial suture (15-27.5 (27.5) long). Genital plates (152.5-165 (157.5) long; 142.5-152.5 (142.5) wide). Additional measurements: Cx-1 (252-285 (257) long (total); 84-122 (108) long (medial)); Cx-3 (317-377 (318) wide); anterior venter (160-167.5 (165) long). Ventral proportions: gnathosomal bay length/width 1.57-2.16 (2.03); anterior venter/genital field length 0.97-1.10 (1.05); anterior venter length/genital field width 1.05-1.16 (1.16); anterior venter/medial suture 6.00-10.67 (6.00).

Male (Figure 89) (n = 5) (allotypic measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (420-495 (450) long; 355-375 (375) wide) circular with a large spot of coloration medially extending in a thin strip anteriorly to the edge of the dorsal plate, coloration variable from navy blue to purple to pink. Anterio-medial platelets (1.80-2.30 (2.18) long; 50-62.5 (55) wide). Anterio-lateral platelets (135-152.5 (152.5) long; 60-65 (60) wide) free from dorsal plate. Dgl-4 much closer to the muscle scar than to dorsum edge (distance between Dgl-4 130-180 (165)). Dorsal plate proportions: dorsum length/width 1.17-1.32 (1.20); dorsal width/distance between Dgl-4 2.06-2.73 (2.27); anterio-medial platelet length/width 1.80-2.30 (2.18); anterio-lateral platelet length/width 2.16-2.54 (2.54); anterio-lateral/anterio-medial length 1.17-1.36 (1.27).

Gnathosoma- Subcapitulum (240-265 (265) long (ventral); 175-196 (196) long (dorsal); 97.5-105 (105) tall) colorless. Rostrum (98.75-107.5 (107.5) long; 35-40 (35) wide) elongate. Chelicerae (225-257 (256) long) with curved fangs (41-51 (50) long). Subcapitular proportions: ventral length/height 2.29-2.56 (2.52); rostrum length/width 2.56-3.07 (3.07). Pedipalps elongate with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (35-47.5 (47.5) long); femur (96.25-103.75 (103.75) long); genu (52.5-57.5 (57.5) long); tibia (77.5-90 (88.75) long; 20-22.5 (20) wide); tarsus (17.5-20 (18.75) long). Palpomere proportions: femur/genu 1.72-1.83 (1.80); tibia/femur 0.81-0.91 (0.86); tibia length/width 3.88-4.44 (4.44).

Venter - (560-590 (581) long; 354-440 (395) wide) colorless. Gnathosomal bay (105-130 (127.5) long; 62.5-77.5 (62.5) wide). Cxgl-4 subapical. Medial suture (67.5-80 (70) long). Genital plates (122.5-135 (127.5) long; 100-110 (105) wide). Additional measurements: Cx-1 (217-269 (255) long (total); 90-119 (115) long (medial)); Cx-3 (264-312 (295) wide); anterior venter (197.5-222.5 (207.5) long). Ventral proportions: gnathosomal bay length/width 1.40-2.04 (2.04); anterior venter/genital field length 1.49-1.65 (1.63); anterior venter length/genital field width 1.80-2.12 (1.98); anterior venter/medial suture 2.53-2.96 (2.96).

Immatures unknown.

Etymology.

Specific epithet ( gnoma ) refers to the dorsal pattern, which, although variable, resembles the head and cap of a gnome (gnoma, L. diminutive fabled being, dwarf).

Distribution.

Eastern, but apparently absent from Appalachians and Northeast (Figure 87).

Remarks.

Torrenticola gnoma groups with other members of the Raptor Complex with high support and specimens of this species were less than 1% different in COI sequence from each other. In the combined analysis, T. gnoma groups with T. irapalpa with high support, but the position of this clade was not recovered. These species are greater than 9% from each other. Based upon overall similarity, distribution, and phylogenetic position, this species is placed within the Raptor 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.