Psochodesmus crescentis Cook, 1896

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 : 1168-1170

Psochodesmus crescentis Cook

(figures 5, 10) Psochodesmus crescentis Cook, 1896: 25 ; Attems, 1899: 370; 1940: 335; Loomis, 1934: 54–55,

figure 27a, b; Chamberlin, 1951: 29; Chamberlin and Hoffman, 1958: 77; Hoffman, 1999:

497; Shelley and Golovatch, 2001: 62; Shelley, 2001: 247.

Diagnosis. Nineteen segments. Preserved specimens thin, fragile and lightly sclerotized, colour tawny. Scalloped margin of collum essentially flat, not or only very slightly upturned; scallops shallowly and subequally separated. Paranota 2 with three lobes, remaining non-poriferous paranota generally with three lobes, caudalmost lobe on 16, 17 and/or 18 sometimes faintly indented to form four barely perceptible lobes; porosteles present on segments 5, 7, 9, 10, 12, 13 and 15, located at caudolateral paranotal corners, with one anterior lobe on segment 5 and two thereafter (figures 5, 10).

Variation. The scallops on the collum are always shallowly segregated, and the condition of the paranotal lobes through segments 15–16 does not vary. However, the paranota on segments 16–18 show either three lobes or four very faint ones, based on a very slight indentation of the caudalmost lobe to form two barely perceptible sublobes. More often, there are just three lobes. The paranotal configuration, with porosteles at the caudolateral corners, is similar to that of species of Poratia , except there are two lobes anterior to the porosteles in Psochodesmus crescentis (only one on segment 5) and one anterior lobe throughout the body in Poratia .

Ecology. Habitat notations with specimens examined during this study include ‘floodplain of stream in hammock’, ‘ Pinus clausa litter’, ‘mixed woods’, ‘hardwood litter’, ‘deep soil extraction, hardwood forest’, ‘oak palm forest’, ‘ Eciton sp. nest’, ‘litter of Pinus sp. ’ and ‘sand pine litter’.

Overall distribution. Psochodesmus crescentis is known only from peninsular Florida, where it may be endemic.

Occurrence in the USA. The type locality is Crescent City, Putnam County, and P. crescentis is also known from between Crescent City and Palatka; Vero Beach , Indian River County ; and Coconut Grove , Dade County ( Loomis , 1934). Causey (1960) gave the range as ‘ Putnam Co. to the end of the peninsula’, and Hoffman (1999) recorded it as the southern two-thirds of the Florida peninsula. Causey’s characterization is reasonably accurate, as the species actually extends from Clay County (just north of Putnam ) to the southern tip of the peninsula (figure 2) .

Published records. Florida: Dade, Highlands, Indian River and Putnam Cos (Cook, 1896; Loomis, 1934; Chamberlin, 1951).

New records. Florida : Alachua Co., Magnesia Springs , ca 4 mi (6.4 km) W Hawthorne, juv. X, 21 September 1963, F. W. Mead ( FSCA) . Brevard Co., Merritt I., Kabboord Sanctuary , 1.5 mi (2.4 km) E FL hwys 3 and 520, XX, juvs, 23 February 1996, G. Steck, P. Skelley and Sutton ( FSCA) . Broward Co., Deerfield Beach , 2 X, February 1959, and X, 20 October 1959, H. A. Denmark ( FSCA) . Clay Co., 5 mi (8 km) W Green Cove Springs , fragment, 7 June 1928, collector unknown ( NMNH) ; and 1.5 mi (2.4 km) NE Middleburg , 4 X, 8 August 1958, L. Hubricht ( VMNH) . Dade Co., Miami , Matheson Hammock, 3 X, 4 July 1977, R. M. Shelley ( NCSM) , XX, 9 July 1986, Klimaszewski, S. Peck ( NCSM) , X, 27 August 1986, S. and J. Peck ( NCSM) , and W, 9 December 1986, S. and J. Peck ( NCSM) ; S. Miami, 7900 SW 176th St. , Old Cutler Hammock Park, X, 15 November 1985, S. and J. Peck ( NCSM) ; and Everglades National Park , Royal Palm Hammock, X, 9 July 1986, S. and J. Peck ( NCSM) . DeSoto / Highlands / Okeechobee Cos, along FL hwy 70 between Arcadia and Okeechobee, 4 X, 10 April 1973, H. F. Loomis ( VMNH) [plotted in DeSoto Co. in figure 2]. Hernando Co. , along FL hwy S- 595, 5 mi (8 km) S jct. FL hwy 50, 10 X, 13 March 1966, P. C. Drummond ( FSCA) ; and Brooksville , XX, 7 November 1929, H. F. Loomis ( VMNH) . Highlands Co., Highlands Hammock St. Park, XX, 15 June 1955, H. S. Dybas ( FSCA) and WW, XX, 1 June 1958, N. B. Causey ( FSCA) ; and Lake Placid , W, 2 X, 7 April 1950, D. E. Beck ( NMNH) and Archbold Biological Station , W, 1958, N. B. Causey ( FSCA) . Hillsborough Co., Tampa, XX, March 1898, collector unknown ( NMNH) . Indian River Co., Vero Beach, X, 22 April 1933, H. F. Loomis ( NMNH) . Lake Co., between Astor and Astor Park, X, juv., 10 October 1929, collector unknown ( NMNH) . Marion Co., 10 mi (16 km) N Ocala , 5 X, juvs, March 1931, O. F. Cook ( NMNH) ; 1.5 mi (2.4 km) S Moss Bluff , W, 22 May 1958, M. H. Muma ( FSCA) ; and Juniper Springs , juv., 21 December 1959, H. A. Denmark ( FSCA) . Pasco Co., Dade City, XX, juvs, 8 December 1928, O. F. Cook ( NMNH) . Putnam Co., locality unknown, 2 X, 5 March 1950, A. Van Pelt ( FSCA) ; and Welaka , University of Florida Reserve, 2 X, 8 April 1964, H. A. Denmark ( FSCA) . Seminole Co., 4 mi (6.4 km) NE Oviedo , 4 X, 10 November 1962, M. H. Muma ( FSCA) . Volusia Co., DeLeon Springs, XX , 10 October 1929, H. F. Loomis ( VMNH) and X, 12 June 1983, R. M. Shelley and J. L. Staton ( NCSM) .

Remarks. Loomis (1961: 100, figure 4a) published a line drawing of the left gonopod of P. crescentis without an accompanying taxonomic account.

Causey (1960) stated that P. crescentis is the ‘most abundant micropolydesmoid on the Florida peninsula’ and is ‘well established in rural areas’; it should be classified as a ‘ Florida endemic or a species known only from this state’, according to the criteria of Shelley (2001). The fragment from west of Green Cove Springs, Clay County, consists of only a few anterior segments, not enough to determine sex (not including segment 7) but enough to identify it positively as P. crescentis by the configurations of the paranota on both poriferous and non-poriferous segments.