THOMPSON: Humboldtiana from Chihuahua and Texas
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Table 3. Humboldtiana cicatricosa n. sp. Measurements in mm based on the holotype (UF 317169) and the two paratypes. Only the holotype appears to be mature because of its reflected peristome.
 H W AW AH Whorls H/W AW/W AH/H AW/AH
Holotype 24.9 27.8 16.3 19.6 3.5 0.90 0.59 0.79 0.83
Paratypes 
UF317175 24.0 26.2 14.6 17.6 3.4 0.92 0.56 0.73 0.83
UF317173 25.0 26.5 15.0 17.5 3.4 0.94 0.57 0.70 0.86
mm), It is rather stout and tapers to the flagellum. The epiphallus is lined internally with four longitudinal fleshy columns. The flagellum is slender, and is about equal to the combined length of the penis + epiphallus (29, 28 mm). The interior of the flagellum has four longitudinal fleshy folds. The vagina is about 1.5 times the length of the penis (14, 15 mm). The lower vagina is about half the length of the middle vagina. The free vagina is not visible. The vagina has four dart-sacs near its middle. Each dart-sac has two exposed dart-bulbs. The upper end of the vagina has four discrete dart-glands that form a ring around the top the middle vagina. The dart-glands are widely separated from the dart-sacs. The spermathecal duct is very long. The combined lengths of the duct + spermatheca are 52, 49 mm long. The spermathecal duct lacks a caecum. The spermatheca is bean shaped and 9, 8 mm long.
Type locality. Chihuahua, 4 km north-northeast of Rancho Blanco, ca. 31 km NNE of San Juanito, along the highway from La Junta to Creel (28 10.7' N, 10723.5' W); 2180 m alt. Holotype: UF 317169; collected 8 August, 2003 by Fred G. Thompson and Elizabeth Mihalcik. Paratypes: UF 317175 (1), UF 320068 (1); same data as holotype; UF 317173 (2), 320068 (1), ITCV (1); same locality as holotype; collected 11 August, 2003.
The type locality is on an east-facing slope of a granite bluff along the west side of the highway in a pine-oak forest. There was a heavy ground cover of oak leaves and some pine needles. Humboldtiana cicatricosa was very sparse in scattered clusters of damp oak leaves following a rain during the previous night. No association with the granite outcrop was apparent.
Distribution. Known only from the type locality.
Remarks. The subgenus Gymnopallax is unique within Humboldtiana by having a mottled patter of dark spots on the lighter gray mantle. Also, it is unusual by lacking a caecum on the spermathecal duct.The subgenus Oreades Thompson & Brewer, 2000 (H. porterae Thompson & Brewer, 2000) is like
Gymnopallax by lacking a spermathecal caecum, but it has few other similarities. Oreades lacks a verge, dart glands and dart sacs, and the mantle is uniform gray.
Humboldtiana cicatricosa and H. sylvania are unusual by having the early whorls of the shell denuded of the periostracum, allowing the early whorls to become badly pitted from erosion. The periostracum may wear off in other species, but the degree and consistency of this trait coupled with unique anatomical states suggests that the causes of the denuded apexes of these two species are intrinsic and are not due just to wear. Humboldtiana cicatricosa differs from H. sylvania by lacking distinct bands on the shell, and by having a smaller shell. The latter species has well defined bands and the shell is about 35 mm wide.
Etymology. The species name is from the Latin cicatricosus, meaning scarred, and refers to the pitted condition of the early whorls of the shell.
Humboldtiana sylvania Thompson & Mejia, 2006
Humboldtiana sylvania Thompson & Mejia, 2006; Nautilus, 120, p. 21.
Type locality. Chihuahua, Corareachi, 4.4 km north, 0.4 km west of Baqueachi (27 28.45' N, 10730.93' W); 2000 m alt.. Holotype: UF 353714; collected 31 August, 2003 by Omar Mejia.
Corareachi is a very small village, which is unnamed on the INEGI topographic map series 1:50,000 (G13A32). The type locality is in a Pinus-Quercus forest in a grassy glen.
Distribution. Known only from the type locality.
Remarks. This recently described species is found in an area that is approximately 100 km south of the type locality for Humboldtiana cicatricosa.
Clydonacme, n. subgen.
Type species. Humboldtiana regula, n. sp. Referred species are Humboldtiana speclabile n. sp.,