Myrmecodesmus formicarius Silvestri, 1910

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 : 1171-1172

Myrmecodesmus formicarius Silvestri

(figures 6, 13, 14)

Myrmecodesmus formicarius Silvestri, 1910: 360 , figure 5; 1911: 193, figures 15, 16; Attems, 1940: 312, figures 447–450; Loomis, 1968: 50; Hoffman, 1973: 513–515, figures 1, 2; 1999: 493; Shear, 1977: 254; Shelley and Golovatch, 2001: 60, figures 1, 2; Shelley, 2001: 247.

Ilyma cajuni Loomis, 1944: 175–177 , figures 6a, b; Chamberlin and Hoffman, 1958: 76–77.

Ilyma colotlipa Chamberlin, 1942: 9 , pl. 1, figures 8–10; 1943: 64; Loomis, 1968: 49. New Synonymy.

Myrmecodesmus colotlipa: Shear, 1977: 254 ; Hoffman, 1999: 492.

Diagnosis. Twenty segments. Preserved specimens hard, heavily sclerotized, usually dark brown, grey, or black in colour. Scalloped margin of collum not or only very slightly upturned; scallops very shallowly and equivalently separated. Paranota 2 with three lobes, remaining paranota with two lobes; poriferous paranota with porosteles positioned between lobes, anterior lobe much larger than caudal. Porosteles present on segments 5, 7, 10, 13 and 15. Paramedian tubercles fused into prominent crests; those on caudal segments narrowly and shallowly segregated, overhanging and extending beyond level of caudal extremity of epiproct, concealing latter in dorsal view (figures 6, 13, 14).

Variation. The degree of indentation of the scallops on the collum varies considerably, from the slightly indented lobes illustrated by Shelley and Golovatch (2001: figures 1, 2) to deep indentations that are subsimilar to the condition in C. sanctus .

Ecology. The types of I. cajuni were collected under the bark of orange trees. The sample from Cameron County, Texas, was encountered ‘under palm logs’, but most of the new samples from Texas were taken in caves .

Overall distribution. The type locality, the southernmost known site, is Xalapa , Veracruz, Mexico (Silvestri, 1910; Attems, 1940; Loomis, 1968; Hoffman, 1973), and M. formicarius ranges northward into northern Texas (figure 1). It is also known from southeastern Louisiana, an area including the type locality of the synonym, I. cajuni, Venice, Plaquemines Parish .

Occurrence in the USA. Myrmecodesmus formicarius occurs from the Rio Grande Valley in the southern tip of Texas northward to Dallas County [a distance of some 445 mi (712 km)] and westward to Sutton County. This coherent distribution, extending northward from Veracruz, appears to be natural, and the species appears to be indigenous to this area. It is also known from Pointe Coupee, Plaquemines and Orleans parishes, Louisiana, a detached area that I believe results from human importations. The record of M. digitatus from Calhoun County, Florida (Hoffman, 1999), that was assigned to M. formicarius by Shelley and Golovatch (2001), is returned to M. digitatus , as a direct comparison with the holotype showed it to be unequivocally this species. Myrmecodesmus formicarius is therefore deleted from Florida, where it was listed as an inhabitant by Shelley (2001).

Published records. Texas: Cameron, Goliad and Guadalupe Cos (Loomis, 1959; Hoffman, 1973; Shelley and Golovatch, 2001). Louisiana: Orleans, Plaquemines and Pointe Coupee Pars (Loomis, 1944; Hoffman, 1973, 1999; Shelley and Golovatch, 2001).

New records. Louisiana: Plaquemines Par., Boothville, X, 22 January 1950, G. H. B. ( FSCA) .

Texas: Bexar Co., Camp Bullis, Lone Gunman Pit , X, 23 October 1997, P. Sprouse and G. Veni ( TMM) . Burnet Co., Simon Says Sink , 12 mi (19.2 km) NE Burnet, X, 12 November 1990, J. R. Reddell and M. Reyes ( TMM) ; and Marble Falls, Railroad Cave ( Cv. ), X, 5 September 1993, A. G. Grubbs, T. Whitfield and G. Hoese ( TMM) . Caldwell Co., Maxwell, WW, XX, 1 December 1963, R. O. Albert ( FSCA) . Cameron Co., near Southmost, Rabb Ranch, WW, XX, 12 December 1954, L. Hubricht ( VMNH) . Comal Co., Camp Bullis, Camp Bullis Cv. No. 1, X, 25 January 2000, J. R. Reddell and M. Reyes ( TMM) . Dallas Co., DeSoto , off FM 1382, Whitewater Trail, X, 17 March 2002, C. T. McAllister ( NCSM) . Goliad Co., Goliad St. Park, X, 7 April 1954, L. Hubricht ( VMNH) . Guadalupe Co., Sequin , near Guadalupe R., W, X, 4 June 1955, L. Hubricht ( VMNH) . Hays Co., Ladder Cv. , 11 mi (17.6 km) W San Marcos, juv., 26 May 1989, A. Grubbs and J. R. Reddell ( TMM) . Kendall Co., ‘ The Crack ,’ X, 28 May 1990, D. Pate ( TMM) . Kerr Co., Kerrville, WW, XX, 20 April 1962, R. O. Albert ( FSCA) ; and 5 mi (8 km) S Kerrville on Guadalupe R., W, X, 20 April 1962, R. O. Albert ( FSCA) . Sutton Co., Caverns of Sonora , upper rest area, X, 9 December 1997, G. Veni ( TMM) . Travis Co., Austin, 9 mi (14.4 km) SSE State Capitol , Goat Cv., X, 23 January 1991, J. R. Reddell and M. Reyes ( TMM) , 10 mi (16 km) SSE State Capitol , Midnight Cv., X, 29 October 1999, M. Sanders ( TMM) , 12 mi (19.2 km) NW State Capitol , Wooden Derrick Cv., X, 14 April 1991, W. Elliott ( TMM) , 12 mi (19.2 km) NW State Capitol, Rockpile Cv. , 3 X, 3 February 1989, J. R. Reddell and M. Reyes ( TMM) , and 13 mi (20.8 km) NW State Capitol , Cactus Pit, X, 19 June 1997, J. R. Reddell and M. Reyes ( TMM) ; and along Buttercup Cr., Karst Area , Windmill Cv., X, 26 September 2000, J. R. Reddell, M. Reyes and M. Warton ( TMM) . Williamson Co., 2 mi (3.2 km) S Georgetown, Inner Space Caverns, X, 22 December 1968 to 5 January 1969, W. Elliott ( TMM) ; Sun City, 10 mi (16 km) NW Georgetown, Do Drop In Cv. , W, 28 July 1995, W. Elliott ( TMM) and 12 mi (14.4 km) NW Georgetown , Good Omen Cv., X, 30 July 1994, J. R. Reddell and M. Reyes ( TMM) ; Georgetown, S Bluff of N. San Gabriel R., Paleospring Cv. , 2 X, 28 July and 2 August 1994, P. Sprouse and B. Larsen ( TMM) ; 3 mi (4.8 km) W Round Rock , Buck Pride Cv., W, 4 X, 21 and 29 May 1996, J. R. Reddell and M. Reyes ( TMM) ; Lakeline Cv. , 1 mi (1.6 km) W jct. FM620 and US hwy 183, X, December 1985, D. L. Pate ( TMM) and X, 19 October 1990, J. R. Reddell and M. Reyes ( TMM) ; Jug Cv. , 2 mi (3.2 km) N jct. FM620 and US hwy 183, X, 14 March 2000, J. R. Reddell, M. Reyes, P. Sprouse and G. Veni ( TMM) ; and Raccoon Cv. , 1 mi (1.6 km) N jct. US hwy 183 and FM620, X, 27 March 1990, J. R. Reddell and M. Reyes ( TMM) .

Remarks. The distributions of M. formicarius and digitatus in the USA parallel to some degree those of the two species of Desmonus Cook ( Polydesmida : Sphaeriodesmidae ), which are unquestionably indigenous. Desmonus pudicus (Bollman) ranges from Nuevo León, Mexico, northward through Texas to southwestern Missouri, and D. earlei Cook occurs along the Gulf Coast from eastern Mississippi to northern Florida, extending northward to southwestern Virginia and central Kentucky (Shelley, 2000). The distributions of M. formicarius and digitatus , though less extensive, demonstrate this same pattern, suggesting that most of their occurrences are native as well. One species, M. formicarius , ranges northward from Mexico a substantial distance into the USA, and the other, M. digitatus , occurs along the Gulf Coast.

I place M. colotlipa in synonymy based on concordance in somatic features, particularly the crests on the caudal segments, which exhibit the configuration illustrated in figures 13, 14. The type locality is Cueva de Jutxlahuaca, at or near Colotlipa, Guerrero, Mexico, some 190 mi (304 km) WSW of Xalapa, the type locality of M. formicarius . The type collection (NMNH) houses two vials of I. colotlipa , one containing three females and juvenile ‘types’, collected in this cave by F. Bonet on 16 May 1941, and the other containing a male and an unknown number of female ‘paratypes’, all highly fragmented, taken there by the same collector on 16 January 1941. The latter sample is so highly fragmented that I could not even determine the total number of individuals, but one piece does contain a gonopodal aperture, so there was at least one male. The gonopods are not in the aperture and are lost, so new collections are needed to compare their structures against published drawings of M. formicarius (Hoffman, 1973: figures 1, 2). However, the virtually identical somatic features and the fact that the native occurrence of M. formicarius ranges much farther northward from Xalapa than the distance westward to Guerrero lead me to propose this synonymy.