Poratia digitata (Porat)

Shelley, R. M., 2004, The milliped family Pyrgodesmidae in the continental USA, with the first record of Poratia digitata (Porat) from the Bahamas (Diplopoda: Polydesmida), Journal of Natural History 38, pp. 1159-1181 : 1164-1166

Poratia digitata (Porat)

(figure 3)

Scytonotus digitatus Porat, 1889: 59 .

Poratia digitata: Cook and Cook, 1894: 238 ; Attems, 1899: 360, pl. 15, figure 350; 1940: 273–274, figures 389–390; Loomis, 1961: 98; 1964: 73–74; 1968: 51; 1972: 201; Hoffman, 1999: 496; Golovatch and Sierwald, 2001: 185–187, figures 1–4, 9–12; Shelley and Golovatch, 2001: 62, figure 3; Shelley, 2001: 247.

Poratioides virginalis Loomis, 1970: 132 , figures 2, 3; Hoffman, 1999: 497.

Poratioides disparatus Loomis, 1973: 322–323 , figures 1, 2; Hoffman, 1999: 497.

Diagnosis. Nineteen segments including epiproct. Preserved specimens thin, fragile and lightly sclerotized, colour whitish. Scalloped margin of collum upturned to varying degrees, usually strongly; scallops, except for two lateralmost on both sides, completely segregated from each other, usually widely, lateralmost ones fused basally (figure 3). Paranota 2 with three lateral lobes, remaining non-poriferous paranota with three lobes. Porosteles present on segments 5, 7, 9, 10 and 15, positioned at caudolateral corners of paranota, with one anterior lobe.

Variation. The degree of upturn of the collum margin varies as does the degree of separation of the adjacent lobes, and individuals with less upturn and separation can be mistaken for Psochodesmus crescentis because of their similar paranotal configurations, although there is only one lobe anterior to the porostele rather than two. In such a tiny milliped, it is sometimes hard to discern the lobes on the collum; I find the most definitive feature of Poratia to be the distinctively different lateralmost lobes, which are fused basally and shallowly segregated. This feature diagnoses Poratia , and the number of segments determines the species.

Ecology. Habitat information on vial lables in this study include ‘in trash pile’, ‘along railroad’ and ‘cypress sawdust pile’.

Overall distribution. The type locality is a greenhouse in Sweden (Porat, 1889). Poratia digitata also occurs in the US Virgin Islands, Costa Rica, Panama and Indonesia, greenhouses in Paris, France, and Germany, and botanical gardens in Germany, Denmark, Switzerland and Great Britain (Attems, 1899; Silvestri, 1923; Schubart, 1947; Loomis, 1961, 1964, 1968, 1970; Blower, 1986; Pedroli-Christen, 1993; Adis et al., 2000; Golovatch and Sierwald, 2001). Adis et al. (2000), Golovatch and Sierwald (2001) and Shelley and Golovatch (2001) reported that P. digitata is an obligatory greenhouse species in Europe and is presumed to be native to Central America/the Neotropical realm.

Occurrence in the USA. Introduced into and established in urban environments in peninsular Florida from Alachua County southward to the Keys; known sporadically elsewhere in association with greenhouses and plant nurseries as far north as northern Illinois (figures 1, 2). Poratia digitata also occurs in the US Virgin Islands (Loomis, 1970; Golovatch and Sierwald, 2001; Shelley and Golovatch, 2001); Golovatch et al. (2001) stated that P. digitata is free-living in the southern USA but occurs strictly in greenhouses in the north. The population in the Bahamas is also free-living.

Published records. Florida: Florida in general (Adis et al., 2000). Dade County (Co.), Miami (Loomis, 1973; Shelley and Golovatch, 2001). Illinois: Cook Co., Chicago, greenhouse at Lincoln Observatory (Golovatch and Sierwald, 2001).

New records. Bahamas: Andros I., 0.6 mi (1 km) S Stafford Cr., Forfar Field Sta., 3 X, October 1980, NCSM Expedition ( NCSM). New Country Record .

USA: Florida: Alachua Co., Gainesville , University of Florida Pharmacy Gardens , ca 15 X, 4 November 1959, P. C. Drummond ( FSCA) . Dade Co., Miami, 5355 SW 92nd St. , ca 10 X, November to December 1972, H. F. Loomis ( FSCA, NCSM) and Matheson Hammock , 3 X, 4 July 1977, R. M. Shelley ( NCSM) ; South Miami, Chapman Field , 4 X, 30 September 1928, collector unknown ( NMNH) . Hillsborough Co., Plant City , 3 X, 2 December 1941, A. B. Gurney ( NMNH) . Manatee Co., Bradenton , 4 X, 2 December 1966, C. J. Bickner ( FSCA) . Monroe Co., Lower Matecumbe Key, X, 16 December 1959, R. E. Woodruff ( FSCA) . Pinellas Co., nr Tarpon Springs, X, 29 September 1959, R. E. Woodruff ( FSCA) ; and Largo, Indian Rocks Nursery , 3 X, 22 October 1970, K. Hickman ( FSCA) . Sumter Co., Oxford , 6 X, juv. X, 11 October 1971, L. Hubricht ( VMNH) .

Louisiana: Calcasieu Par., Lake Charles, Duggan’s Greenhouse, 3 X, 2 August 1964, M. Kordish ( FSCA). East Baton Rouge Par. , Baton Rouge , Louisiana State University campus, nr Audubon Hall , earthworm culture, juv., 27 September 1964, R. E. Tandy ( FSCA) . New State Record.

Illinois: Champaign Co., Urbana , in greenhouse, 3 X, 5 April 1953, collector unknown ( INHS) .

Texas: Jim Wells Co., Alice, Green Thumb Nursery , 4 X, 22 September 1961, R. O. Albert ( FSCA). New State Record .