Torrenticola robisoni 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 robisoni Fisher & Dowling sp. n.

Material examined.

HOLOTYPE (♀): from USA, Arkansas, Polk County, East Saline Creek, 30 Jul 2011, by IM Smith, IMS110041

PARATYPES (1 ♀; 0 ♂): Oklahoma, USA: Pushmataha County, beside Route 271, Walnut Creek (34°39'N 95°7'W), 1 Jul 1987, by IM Smith, IMS870063A

Type deposition.

Holotype (♀) deposited in the CNC; paratype (1 ♀) deposited in the ACUA.

Diagnosis.

Torrenticola robisoni are similar to other members of the Erectirostra Group ( T. karambita and T. erectirostra ). They are similar to other species with similar dorsal patterning, but can be differentiated from these by having a dentate, upturned rostrum that is wide when viewed ventrally. T. robisoni can be differentiated from T. erectirostra by having more elongate anterio-lateral platelets (length/width ♀ = 2.96-3.00 in T. robisoni , 2.52-2.69 in T. erectirostra ). T. robisoni can be differentiated from T. karambita by having dorsal coloration ( T. karambita is colorless) and having a more elongate rostrum (length/width ♀ = 2.09-2.09 in T. robisoni , 1.57-1.62 in T. karambita ). T. robisoni can be further differentiated from T. erectirostra and T. karambita by being distributed in the Interior Highlands, while the others are in the Appalachians.

Description.

Female (Figure 224) (n = 2) (holotype measurements in parentheses when available) with characters of the genus with following specifications.

Dorsum- (650-670 (650) long; 455-500 (455) wide) ovoid with reddish purple coloration separated into anterior and posterior portions with orange medially. Anterio-medial platelets (147.5-150 (150) long; 60-62.5 (60) wide). Anterio-lateral platelets (200-210 (200) long; 67.5-70 (67.5) wide) free from dorsal plate. Dgl-4 closer to the edge of the dorsum than to the muscle scars (distance between Dgl-4 305-340 (305)). Dorsal plate proportions: dorsum length/width 1.34-1.43 (1.34); dorsal width/distance between Dgl-4 1.47-1.49 (1.49); anterio-medial platelet length/width 2.36-2.50 (2.50); anterio-lateral platelet length/width 2.96-3.00 (2.96); anterio-lateral/anterio-medial length 1.33-1.42 (1.33).

Gnathosoma - Subcapitulum (325-335 (325) long (ventral); 218-250 (218) long (dorsal); 125-132.5 (132.5) tall) colorless. Rostrum (115-120 (115) long; 55-57.5 (55) wide) wide and upturned with dentation. Chelicerae (315-330 (315) long) with curved fangs (46-50 (46) long). Subcapitular proportions: ventral length/height 2.45-2.68 (2.45); rostrum length/width 2.09-2.09 (2.09). Pedipalps short and stocky (especially tibiae) with tuberculate ventral extensions on femora and genua. Palpomeres: trochanter (52.5-52.5 (52.5) long); femur (95-107.5 (95) long); genu (60-62.5 (60) long); tibia (47.5-58.75 (47.5) long; 25-27.5 (25) wide); tarsus (15-17.5 (15) long). Palpomere proportions: femur/genu 1.58-1.72 (1.58); tibia/femur 0.50-0.55 (0.50); tibia length/width 1.90-2.14 (1.90).

Venter - (779-825 (779) long; 543-550 (543) wide) colorless. Gnathosomal bay (165-190 (165) long; 115-120 (115) wide). Cxgl-4 far from apex. Medial suture (12.5-20 (12.5) long). Genital plates (168.75-202.5 (202.5) long; 157.5-180 (180) wide). Additional measurements: Cx-1 (308-350 (308) long (total); 142-155 (142) long (medial)); Cx-3 (367-375 (367) wide); anterior venter (182.5-200 (182.5) long). Ventral proportions: gnathosomal bay length/width 1.43-1.58 (1.43); anterior venter/genital field length 1.05-1.08 (1.08); anterior venter length/genital field width 1.16-1.25 (1.16); anterior venter/medial suture 10.00-14.60 (14.60).

Male unknown.

Immatures unknown.

Etymology.

Specific epithet ( robisoni ) named in honor of Henry W. Robison for his efforts in communicating the importance of the Interior Highlands (Ozarks and Ouachitas)-the type locality-which have a high proportion of endemic species, yet are understudied with respect to other areas of increased endemism (e.g., California floristic province, coastal plains, southern Appalachians, Pacific Northwest). His contributions instill passion for the region to even the casual reader, and have inspired many, including JRF, to pursue biodiversity research in the area.

Distribution.

Known only from the Ouachita Mountains, possibly endemic (Figure 223).

Remarks.

Torrenticola robisoni groups with other members of the Raptor Complex with high support. The single T. robisoni specimen that we were able to include in our phylogenetic analysis is 8-9% different in COI sequence from T. erectirostra and T. karambita . Based upon the distinctive morphology of the gnathosoma of these species, we place them in the Erectirostra Identification group.

This species hypothesis is supported by biogeography, high divergence between species, and by morphological characters outlined in the diagnosis.