Ectinorus (Ichyonus) onychius (Jordan and Rothschild)

Hastriter, Michael W. & Sage, Richard D., 2011, Description of a new species of Ectinorus (E. spiculatus) (Siphonaptera, Rhopalopsyllidae) from Argentina and a review of the subgenus Ichyonus Smit, 1987, ZooKeys 124, pp. 1-18 : 5-8

Ectinorus (Ichyonus) onychius (Jordan and Rothschild) Figs 3, 6, and 8

Parapsyllus onychius Jordan and Rothschild 1923: 352; Dalla Torre 1924: 19; Del Ponte and Riesel 1939: 545.

Ectinorus onychius (Jordan and Rothschild), Jordan 1942b: 11.

Ectinorus onychius onychius (Jordan and Rothschild), Jordan 1942a: 434; Da Costa Lima and Hathaway 1946: 149; Smit 1955: 337 (♀ description); Johnson 1957: 142; Smit 1963: 427; Giménez, Ciccarelli and de la Barrera 1964: 129, 138, 139; Jameson and Fulk 1977: 402 (misdetermination, originally referred to Ectinorus onychius deplexus ); Smit 1987: 116; Beaucournu and Gallardo 1988: 100; Beaucournu and Alcover 1989: 491; Beaucournu and Kelt 1990: 648, 665; Beaucournu and Gallardo 1992: 100; Alarcón 2000: 13; Beaucournu and del Carmen Castro 2003: 468. stat. n.

Ectinorus onychius fueginus Jordan 1942a: 434; Ectinorus onychius fueginus Jordan, Da Costa Lima and Hathaway 1946: 149; Johnson 1957: 142; Smit 1987: 121; Beaucournu and del Carmen Castro 2003:468. syn. n.

Material Examined.

Argentina, Chubut Province: Cholila, ex Ctenomys haigi Thomas, 23 I 1920, H.E. Box (♂ holotype); Cholila, ex Akodon iniscatus Thomas, 23 I 1920, H.E. Box (♂ paratype) (BMNH). Puerto Madryn, 6, 9 IV 1978, A. Kovacs (1♂, 1♀) (JCB). Mendoza Province: Puesto "Pugin", Algattolito (32°53'S, 67°18'W), 620m, ex "rats", D.F. Giménez (♀) (BMNH). Neuquén Province: Laguna Blanca National Park, Locality 40, 1.97 km W, 3.84 km N Mellizo Sud, (39°2'27.5"S, 70°19'24.5"W) inside clumps of "molle" ( Schinus polygama ) on sandy soil, 1290m, ex Abrothrix olivaceus xanthorhinus , 17 II 2006, R.D. Sage (♂, RDS-17963/F-276); Laguna Blanca National Park, Locality 74, 0.04 km E, 3.22 km S Cerro de la Laguna, (39°03'5.03"S, 70°22'30.42"W), Nassauvia shrubland on dry slope above Laguna Blanca, south side of Península de la Laguna Blanca, 1285m, ex Akodon iniscatus (♂), 20 II 2007, R.D. Sage(♂, RDS-18370/F-282) (BYU); Laguna Blanca National Park, Locality 52, 0.27 km E, 3.93 km N Cerro de la Laguna, (38°59'9.84"S, 70°22'7.02"W), grass scrubland ( Berberis sp. and Colletia sp.) on east facing slope of rimrock, 1340m, ex Euneomys chinchilloides (Waterhouse) (♂), 27 VII 2007, R.D. Sage (2 ♀, RDS-18493) (MACN); Laguna Blanca National Park, Locality 76, 2.24 km W, 3.12 km S Cerro Mellizo Sud, (39°6'10.92"S, 70°19'33.42"W), lava outcrops with Colliguaja sp., 1320m, ex Phyllotis xanthopygus (Waterhouse) (♂), 13 III 2007, R.D. Sage. (♀, RDS-18397) (BYU); Currhué Chico, ex Akodon olivaceus = Abrothrix olivaceus Waterhouse, 22 IV 1988, J.C. Beaucournu (♂); Lago Currhué, Akodon longipilis = Abrothrix longipilis Waterhouse, IV 1988, J.C. Beaucournu (♂); Lago Norquínco, ex Abrothrix longipilis , 1 V 1988, J.C. Beaucournu (2♀) (JCB). Río Negro Province: Trap line #6, Península Llao Llao, 0.4 km N Park Guard Station between Lagos Perito Moreno and Escondido, (41°02'54.7"S, 71°33'56.5"W) in green bamboo/ coíhue forest, 831m, ex Loxodontomys micropus Waterhouse (♀), 6 V 2005, R.D. Sage (♂, RDS-17339/F-278) (BYU); San Pedro, nr. Bariloche, ex "nest of Rattus norvegicus ", 20 II 1954, J.M. de la Barrera (3♂, 1♀); San Pedro, nr. Bariloche, ex Hesperomys sp. [most likely a representative of either Oryzomyz longicaudatus or Akodon longipilis ], 27 II 1954, J.M. de la Barrera (3♂, 2♀); San Pedro, nr. Bariloche, ex Euneomys dabbenei = Ectinorus chinchilloides , 8 VII 1953, J.M. de la Barrera (♀ paratype, "neallotype" on slide); Península of San Pedro, Bariloche, ex Akodon varius neocenus = Akodon neocenus Thomas [surely refers to Akodon iniscatus , since Akodon neocenus is only known to occur 150 km east of the Bariloche region, with Akodon iniscatus filling in the intervening area], 20 III 1960, J.M. de la Barrera (♀); Península of San Pedro, Bariloche, ex Oryzomys longicaudatus philippii = Oligoryzomys longicaudatus (Bennett), 20 III 1960, J.M. de la Barrera (♀); Bariloche, Nahual Huapi, ex Rattus sp., J.M. de la Barrera (1 male); El Bolsón, ex "nest of rodent", G. Topali & Don J. Szabo (♂); San Carlos de Bariloche, ex Akodon olivaceus beatus = Abrothrix olivaceus , 14 I 1965, J.M. de la Barrera (♀) (BMNH); San Pedro, nr Bariloche, ex Oligoryzomys longicaudatus , 26 II 1954, J.M. de la Barrera (♂); El Bolsón, 20 I 1961, Topal Gy. No. 58 (♀) (CMHN). Tierra del Fuego Province: Estancia Viamonte, ex Belonopterus chilensis = Vanellus chilensis Molina, 15 X 1931, P.W. Reynolds ( Ectinorus onychius fueginus ♂ holotype, new synonymy herein) (BMNH). Chile, Aisén Region: Chico Aerodromo, ex Akodon xanthorhinus = Abrothrix olivaceus xanthorhinus , III 1987, J.C. Beaucournu (Kelt-3976, 3♂, 1♀); Puerto Ibanéz, El Salto, ex Akodon longipilis = Abrothrix longipilis , III 1987, J.C. Beaucournu (Kelt-3563, ♂, ♀) (BYU).

Diagnosis.

Ectinorus onychius males differ from either Ectinorus angularis and Ectinorus deplexus by the lack of a strong lobe on the ventro-caudal margin of the distal arm of the ninth sternum, by fewer strong setae on the caudal margin of the telomere with only 4 (sometimes 5) (Fig. 3), and the hyaline crochet is longer than wide and round on the apex (without sclerotized margins or special feature at ventro-caudal margin) (Fig. 6). Note: the crochet of Ectinorus onychius specimens from Aisén Region, Chile is more similar to the single exemplar of Ectinorus angularis in Magallanes Region, Chile than the more northern populations of Ectinorus onychius in Chubut, Neuquén, and Rio Negro Provinces, Argentina. Never-the-less, populations further north in Argentina and those in Aisén Province, Chile are clearly distinct from Ectinorus angularis by the greater superior position of the acetabulum on the telomere. Female distinguished from Ectinorus angularis by the much longer anal stylet (cf. Figs 7 and 8)

Remarks.

There is insufficient morphological evidence to support the erection of Ectinorus onychius fueginus to full specific status, nor to recognize this single specimen as a subspecies. It is considered a junior synonym of Ectinorus onychius from which it is indistinguishable. Our taxonomic re-interpretation extends the geographic range of Ectinorus onychius from northeastern Mendoza Province to the extreme southern province of Tierra del Fuego, and from the Atlantic coast (Puerto Madryn) to steppe habitat at the Argentina/Chilean border. Additional collections in the southern parts of the Monte phytogeographic biomes of Mendoza/La Pampa/ Río Negro Provinces and in the south-central parts of the Patagonian region are needed to establish the distribution and true range of this species. The finding of the record on a plover, [ Belonopterus chilensis = Vanellus chilensis ] (Tierra del Fuego Province) is certainly accidental and is the only known record of the subgenus found on an avian host. Representatives of Ichyonus appear on many small sigmodontid rodents and without specificity. There is only one report of this species on a non-sigmodontid rodent, i.e., on the histricomorphid genus Ctenomys . The nearly total absence of this flea in our extensive study of ectoparasites of species of Ctenomys would suggest this is an accidental association. In addition to hosts previously reported on Ectinorus onychius (in lit.), our findings on Phyllotis xanthopygus , Abrothrix olivaceus xanthorhinus , Loxodontomys micropus , and Ectinorus chinchilloides are new host records. The reference to Abrothrix xanthorhinus as a subspecies of Abrothrix olivaceus is our attempt to identify the distinct race of this enigmatic sigmodontid complex. This flea is clearly more dependent on terraine, habitat, elevation, and microclimatic conditions than on host specificity.

A single specimen (RDS-17339) was collected from Loxodontomys micropus in the region of the Valdivian, evergreen rainforest. The specific site is in a mature forest of Nothofagus dombeyi (Mirb.) ( “coihue”) with a dense understory of the bamboo Chusquea culeou Desvaux.( “caña coihue") on a south-facing hillside (Fig. 24). There were many fallen and rotting trunks of the “coihue” on the ground, and a thick leaf litter comprised mostly of the bamboo leaves. The soil is dark in color and rich in humus. The environment is cool and moist. Loxodontomys micropus was the third-most abundant of the six rodent species in this habitat, with Abrothrix longipilis being the most common species (40 percent of the total collected at this site) from which Ectinorus onychius was not collected. The second specimen (RDS-18370) was collected from Akodon iniscatus on the large peninsula that juts into Laguna Blanca in LBNP. The peninsula has been protected from livestock grazing for 15 years and has a comparatively very dense development of the Patagonian steppe vegetation. In particular the eastern (leeward) side of the peninsula is densely covered with spiny shrub Nassauvia glomerulosa D. Don ( “uña de gato") and bunch grasses. The soil consists of fine, windblown sand, with little organic matter. The Laguna Blanca area is cool, dry, and strong winds are frequent. On this protected peninsula, Akodon iniscatus is the most abundant species, followed by Eligmodontia morgani J.A. Allen. Two additional specimens (RDS-18493) were collected from, Euneomys chinchilloides along the edge of a black basalt rimrock with a dense growth of the Patagonian steppe shrub Colletia hystrix (Clos.) ("espino negro") and large bunch grasses (Fig. 25). The ground consisted of blocks of the broken basaltic rock and wind-blown sand. Phyllotis xanthopygus was the more common of the five species of rodents trapped in this habitat.

Measurements of the anal stylet of eight specimens were conducted. The range of their length was 58-71µ (average: 63µ) and width was 16-20 µ (average: 18µ) with an average ratio of 3.5 × (length:width). This ratio is substantially greater than that of the single female of Ectinorus angularis (2.1 ×). It is doubtful that the shorter anal stylet is an anomalous condition, since the stylet on both sides are similarly short.