Plagiodontes daedaleus (Deshayes, 1851)

Pizá, Julia & Cazzaniga, Néstor J., 2012, Barrels and pagodas: clarifying the identity and variability of two nominal taxa of carinated land snails in the genus Plagiodontes (Gastropoda: Orthalicidae: Odontostominae), Journal of Natural History 46 (7 - 8), pp. 383-410 : 394-400

publication ID	https://doi.org/ 10.1080/00222933.2011.640440
persistent identifier	https://treatment.plazi.org/id/F16A883F-FFBB-FFBC-8D6F-FBAA846E97EE
treatment provided by	Carolina
scientific name	Plagiodontes daedaleus (Deshayes, 1851)
status

Treatment

Plagiodontes daedaleus (Deshayes, 1851) : carinated forms

Odontostomus (Plagiodontes) weyenberghii minor Parodiz, 1939, p. 729 .

Cyclodontina (Plagiodontes) weyemberghi minor: Parodiz 1957, p. 29 .

Plagiodontes weyemberghi minor: Fernández 1973, p. 154 .

Odontostomus weyemberghii minor: Breure 1974, p. 119 .

Plagiodontes weyemberghii: Breure and Schouten 1985, p. 17 .

Odontostomus weyemberghi minor: Richardson 1993, p. 52 .

Description of specimens from populations including carinated shells

Shell ( Figure 2 View Figure 2 , 3 View Figure 3 , 6 View Figure 6 ). Short, globose to cylindrical, rimate, solid, whitish, 18.8–28.24 mm long by 10.68–14.01 mm wide; with 5 to 7.75 almost straight, flattened whorls. Spire globose of variable length, occupying 22–36% of the shell length. Apex a short and obtuse cone. Aperture subvertical, ovate, 9.37–13.31 mm long by 8.08–11.16 mm wide, with a reflected peristome in adult specimens. The type series of P. weyenberghii minor includes the holotype and 83 paratypes, of which only about 30% have a sutural keel.

Protoconch and teleoconch sculpture ( Figure 7 View Figure 7 E–H). Protoconch, of 2 to 2.5 whorls, with conspicuous axial ribs, crossed by less marked spiral lines with an internal depression ( Figure 7E,G View Figure 7 ). Protoconch–teleoconch boundary not well defined, forming a transition area ( Figure 7E View Figure 7 ). Teleoconch with strong, straight axial ribs with minor undulated spiral elements in the intercostal space ( Figure 7F,H View Figure 7 ).

Apertural lamellae and folds ( Figures 2 View Figure 2 , 3 View Figure 3 ). The studied specimens had 8 to 12 apertural lamellae and folds (mode = 9). Angular fold joined to parietal lamella and supracolumellar denticle in 50% of specimens. Frequencies of lower palatal folds distributed as shown in Figure 8 View Figure 8 .

Pallial complex ( Figure 9C, D View Figure 9 ). Markedly vascularized, 18.8 to 36.53 mm long. Kidney 1.7 times as long as wide and 27% of lung length. Secondary ureter opens in the ureteric pore at the level of the upper third of the kidney. Pericardium 3.13–6.09 mm long, continuous with the prominent pulmonary vein that is 12.53–24.35 mm long. Afferent marginal vein branches out distally, equalling about 52% of the pulmonary vein length. Marginal vein moderately developed. Mantle collar includes a brownish spongy pallial gland and several dents corresponding to the apertural folds and lamellae.

Reproductive system ( Figures 10C,D View Figure 10 , 11C,D View Figure 11 , 12C,D View Figure 12 , 13 View Figure 13 E–H). Ovotestis composed of six or seven groups of digitiform acini. Albumen gland elongated and hyaline whitish. Fertilization pouch–spermathecal complex white and conspicuous, distal part composed of a long convoluted blind sac ( Figure 11C,D View Figure 11 ). Vas deferens emerges above the bifurcation of the vagina to the free oviduct and the bursa copulatrix duct; this bifurcation is marked by a notorious constriction. Bursa copulatrix a round sac, 1.5–3 mm diameter. Bursa copulatrix duct 17.26–39.91 mm long with almost constant diameter; in some specimens slightly swollen distally. Internally, bursa copulatrix duct has straight folds or lamellae. Vagina shorter than or as long as penis (penis length / vagina length 1–2.33), longer than wide (vagina length / vagina width 1.88–3.20), and with a distal widening. Inner vaginal surface with a reticulated aspect ( Figure 12C,D View Figure 12 ).

Penial complex, 29.09–48.71 mm long, occupies a large proportion of the anterior portion of the visceral cavity. Penis, 7.44–14.88 mm long, club-shaped, with a marked proximal swelling 2.84–4.33 mm wide. Penial sheath conspicuous. Internally, the penis has a penial papilla or verge with a large accessory lobe about 70% the size of the papilla ( Figure 13E,F View Figure 13 ). Inner wall of penis with four or five longitudinal folds or pilasters that are prominent, undulated and can be to some extent anastomosed. Epiphallus 8.79–16.91 mm long, cylindrical, and its transition to the penis is clearly marked by a constriction. Internally, it has five straight folds and has a proximal partition at the point where the folds join to form a minute hollow papilla. The epiphallus continues in a cylindrical tube running into the fleshy penial papilla. This tube has an internal sculpture of elevated and branched, anastomosed folds ( Figure 13G,H View Figure 13 ).

The vas deferens insertion demarcates the limit between epiphallus and flagellum. Flagellum, 7.44–16.91 mm long, cylindrical and markedly thinner than epiphallus.

Shell morphometry

Table 1 summarizes morphometric information on the studied shells of P. weyenberghii weyenberghii , P. weyenberghii minor and P. daedaleus . Bonferroni’s corrected t -test results are indicated. Figures 2 View Figure 2 and 6 View Figure 6 show representative shells and living specimens of P. weyenberghii weyenberghii and P. weyenberghii minor .

The MDA produced two discriminant functions ( Tables 2 and 3). DF1 was negatively correlated with SL, LWW and AW; DF2 was positively correlated with SL, LWL, AL, MA and whorl number, but negatively correlated with SA. So, the larger and more slender shells of P. weyenberghii were mostly located towards positive values of both axes ( Figure 14 View Figure 14 ); P. daedaleus specimens located towards negative values of DF1 and positive values of DF2 because of their obese shape and large size, and the shells of P. weyenberghii minor located mainly in central values of DF1 and negative values of DF2 because of their obese shape and smaller size. The percentages of specimens correctly classified were 90.2% in P. weyenberghii , 79.2% in P. daedaleus and only 63.9% in P. weyenberghii minor . Most misclassifications occurred between P. weyenberghii minor and P. daedaleus . An MDA, performed between P. daedaleus and P. weyenberghii to classify P. weyenberghii minor specimens (considered as ungrouped) as either P. daedaleus or P. weyenberghii , resulted in 84.5% of the specimens classified as P. daedaleus and 15.5% as P. weyenberghii ( Tables 2 and 3; Figure 15 View Figure 15 ).