Torrenticola caerulea 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 caerulea Fisher & Dowling sp. n.

Material examined.

HOLOTYPE (♀): from USA, Tennessee, Wayne County, beside service road parallel to Natchez Trace Parkway (35°15'9"N, 87°37'53"W), 27 Sep 2010, by IM Smith, IMS100160, DNA 1882.

PARATYPES (5 ♀; 3 ♂): Tennessee, USA: 2 ♀ from Wayne County, beside Natchez Trace Parkway at Lower Glenrock Branch Picnic Area, (35°15'15"N, 87°37'37"W), 2 June 1992, by IM Smith, IMS920021 • 1 ♂ (ALLOTYPE) from Wayne County, Lower Glenrock Picnic Area off Natchez Trace Parkway, (35°15'15"N, 87°37'37"W), 5 October 2005, by IM Smith, IMS050119A • 1 ♀ and 2 ♂ from Wayne County, Lower Glenrock Picnic Area off Natchez Trace Parkway, (35°15'15"N, 87°37'37"W), 5 October 2005, by IM Smith, IMS050119A • 2 ♀ from Wayne County, beside service road parallel to Natchez Trace Parkway (35°15'9"N, 87°37'53"W), 27 Sep 2010, by IM Smith, IMS100160.

Type deposition.

Holotype (♀), allotype (♂), and some paratypes (3 ♀; 1 ♂) deposited in the CNC; other paratypes (2 ♀; 1 ♂) deposited in the ACUA.

Diagnosis.

Torrenticola caerulea are similar to other members of the Rusetria "Eastern 2-Plates" group ( T. biscutella , T. delicatexa , T. feminellai , T. indistincta , T. malarkeyorum , T. microbiscutella , T. pendula , T. sellersorum , T. tysoni , T. ululata , and T. whitneyae ) 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. caerulea can be differentiated from all other Eastern 2-Plates by having faint blue coloration. T. caerulea can be differentiated from T. ululata and T. feminellai by dorsal coloration and pattern. T. caerulea can be differentiated from T. tysoni by having a less elongate rostrum (length/width = 2.67-2.96 in T. caerulea , 3.06-3.50 in T. tysoni ). T. caerulea can be differentiated from T. pendula by having a more elongate gnathosomal bay (1.40-2.09 in T. caerulea , 2.42-2.90 in T. pendula ) and more elongate pedipalpal tibiae (3.11-3.83 in T. caerulea , 2.78-3.05 in T. pendula ). T. caerulea can be differentiated from T. microbiscutella by having a less elongate dorsum (length/width = 1.32-1.56 in T. caerulea , 1.63-1.75 in T. microbiscutella ). T. caerulea can be differentiated from T. whitneyae by having more elongate pedipalpal tibiae (length/width = 3.11-3.83 in T. caerulea , 2.42-2.95 in T. whitneyae ) and by anterior venter/genital field width (♀ = 0.9-1.04 in T. caerulea , 0.67-0.80 in T. whitneyae ; ♂ = 1.71-1.83 in T. caerulea , 1.5-1.54 in T. whitneyae ). Female T. caerulea can be differentiated from female T. biscutella by having slightly more elongate pedipalpal tibae (length/width = 3.5-3.83 in T. caerulea , 3.35-3.45 in T. biscutella ). Male T. caerulea can be differentiated from male T. biscutella by anterior venter/medial suture (2.4-2.57 in T. caerulea , 2.68-2.83 in T. biscutella ). Female T. caerulea can be differentiated from female T. malarkeyorum , T. sellersorum , T. delicatexa , and T. indistincta by having a thinner genital field (120-145 in T. caerulea , 150-205 in others). Male T. caerulea can be differentiated from male T. indistincta by having a smaller dorsum (length = 405-460 in T. caerulea , 480-645 in T. indistincta ; width = 260-305 in T. caerulea , 315-470 in T. indistincta ). Body proportions of male T. caerulea do not differ from male T. malarkeyorum , T. sellersorum , and T. delicatexa , but can be differentiated by dorsal coloration.

Description.

Female (Figure 36) (n = 5) (holotype measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (550-600 (580) long; 400-440 (440) wide) ovoid with faint blue coloration anteriorly and posteriorly, broadly connected medially. Anterio-medial platelets (125-130 (128.75) long; 40-45 (42.5) wide). Anterio-lateral platelets (145-157.5 (145) long; 57.5-65 (62.5) wide) fused to dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 275-320 (320)). Dorsal plate proportions: dorsum length/width 1.32-1.48 (1.32); dorsal width/distance between Dgl-4 1.25-1.51 (1.38); anterio-medial platelet length/width 2.78-3.25 (3.03); anterio-lateral platelet length/width 2.32-2.48 (2.32); anterio-lateral/anterio-medial length 1.12-1.21 (1.13).

Gnathosoma - Subcapitulum (310-330 (320) long (ventral); 225-245 (240) long (dorsal); 137.5-156.25 (155) tall) colorless. Rostrum (120-135 (125) long; 45-47.5 (45) wide). Chelicerae (310-330 (320) long) with curved fangs (62-70 (65) long). Subcapitular proportions: ventral length/height 2.06-2.25 (2.06); rostrum length/width 2.67-2.84 (2.78). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (40-48.75 (48.75) long); femur (115-120 (120) long); genu (67.5-72.5 (72.5) long); tibia (85-87.5 (87.5) long; 22.5-25 (25) wide); tarsus (17.5-20 (20) long). Palpomere proportions: femur/genu 1.66-1.78 (1.66); tibia/femur 0.71-0.76 (0.73); tibia length/width 3.50-3.83 (3.50).

Venter - (620-750 (660) long; 400-580 (660) wide) with faint blue coloration. Gnathosomal bay (145-175 (145) long; 82.5-116.25 (95) wide). Cxgl-4 subapical. Medial suture absent. Genital plates (155-165 (155) long; 140-145 (145) wide). Additional measurements: Cx-1 (257.5-305 (257.5) long (total); 125-135 (125) long (medial)); Cx-3 (310-380 (380) wide); anterior venter (130-150 (137.5) long). Ventral proportions: gnathosomal bay length/width 1.40-1.94 (1.53); anterior venter/genital field length 0.82-0.97 (0.89); anterior venter length/genital field width 0.90-1.04 (0.95).

Male (Figure 36) (n = 3) (allotypic measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum - (405-460 (460) long; 260-305 (300) wide) ovoid with faint blue coloration anteriorly and posteriorly, broadly connected medially. Anterio-medial platelets (95-106.25 (106.25) long; 35-37.5 (35) wide). Anterio-lateral platelets (117.5-130 (125) long; 40-47.5 (45) wide) fused to dorsal plate. Dgl-4 much closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 190-240 (230)). Dorsal plate proportions: dorsum length/width 1.51-1.56 (1.53); dorsal width/distance between Dgl-4 1.27-1.37 (1.30); anterio-medial platelet length/width 2.53-3.04 (3.04); anterio-lateral platelet length/width 2.74-2.94 (2.78); anterio-lateral/anterio-medial length 1.18-1.24 (1.18).

Gnathosoma - Subcapitulum (220-242.5 (227.5) long (ventral); 165-185 (165) long (dorsal); 87.5-97.5 (97.5) tall) colorless. Rostrum (88.75-92.5 (92.5) long; 30-35 (33.75) wide). Chelicerae (225-232.5 (227.5) long) with curved fangs (42.5-50 (45) long). Subcapitular proportions: ventral length/height 2.33-2.51 (2.33); rostrum length/width 2.64-2.96 (2.74). Pedipalps with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (37.5-37.5 (37.5) long); femur (83.75-87.5 (87.5) long); genu (52.5-55 (55) long); tibia (67.5-70 (67.5) long; 20-22.5 (20) wide); tarsus (15-20 (17.5) long). Palpomere proportions: femur/genu 1.59-1.60 (1.59); tibia/femur 0.77-0.81 (0.77); tibia length/width 3.11-3.38 (3.38).

Venter - (485-550 (550) long; 305-340 (330) wide) with faint blue coloration. Gnathosomal bay (120-127.5 (125) long; 57.5-65 (60) wide). Cxgl-4 subapical. Medial suture (65-75 (75)). Genital plates (110-117.5 (117.5) long; 90-105 (102.5) wide). Additional measurements: Cx-1 (220-220 (220) long (total); 85-95 (95) long (medial)); Cx-3 (240-260 (260) wide); anterior venter (165-180 (180) long). Ventral proportions: gnathosomal bay length/width 1.96-2.09 (2.08); anterior venter/genital field length 1.50-1.57 (1.53); anterior venter length/genital field width 1.71-1.83 (1.76).

Immatures unknown.

Etymology.

Specific epithet ( caerulea ) refers to the overall and diagnostic bluish appearance of this species (caeruleus, L. sky-blue).

Distribution.

Known only from Wayne County, Tennessee (Figure 35). T. caerulea has been collected so rarely that comments about distribution are speculative, but given our collection efforts, it is reasonable to speculate that this species is at least restricted to the southern Appalachians.

Remarks.

Torrenticola caerulea groups with other members of the Rusetria Complex with high support and specimens of this species were less than 1% different in COI sequence from each other. In all analyses, T. caerulea groups with two other morphologically similar species: T. biscutella and T. malarkeyorum . These three species are 3-5% different from each other in COI sequence. The three of these species are morphologically similar to the more distantly-related T. delicatexa , but T. caerulea can be differentiated from all of these by color. The range of T. caerulea overlaps with each of these except for T. biscutella , which is not known from east of the Mississippi River.

This species hypothesis is supported by biogeography, low COI divergence within the species (0-2%) and high divergence between species (3-15%), and by the morphological characters outlined in the diagnosis.