Spixia tucumanensis ( Parodiz 1941 )

Oroño, Eugenia Salas, 2007, Taxonomic review of the Spixia pyriformis species complex (Gastropoda: Pulmonata: Odontostominae), Zootaxa 1498, pp. 1-25 : 20-23

publication ID	https://doi.org/ 10.5281/zenodo.177060
DOI	https://doi.org/10.5281/zenodo.6251592
persistent identifier	https://treatment.plazi.org/id/5975CD10-3B1E-7E31-538D-FE0BFCEBF958
treatment provided by	Plazi
scientific name	Spixia tucumanensis ( Parodiz 1941 )
status

Treatment

Spixia tucumanensis ( Parodiz 1941)

(Fig. 39–49)

Odontostomus (Spixia) tucumanensis Parodiz, 1941: 92 . Odontostomus (Spixia) tucumanensis Parodiz, 1942b: 319 . Cyclodontina (Spixia) tucumanensis Parodiz, 1957: 27 . Spixia tucumanensis Fernández, 1973: 141 .

Holotype: MACN 23108.

Type locality: Argentina, Tucumán, Margins of Salí River, near Tucumán City, A. Shreiter leg., 1919.

Figures 39–42. Spixia tucumanensis . 39. Shell. Holotype MACN 23108. 40. Protoconch general view, scale bar: 100 Μm. 41. General view of juvenile shell with preserved periostracum, from protoconch to seventh whorl, scale bar: 1 mm. 42. Detail of shape of lamella, scale bar: 10 Μm.

Shell (Fig. 39): Subpyriform, 9 1/2 convex whorls. Light brown cupreous with darker axial bands. Protoconch with parallel, straight, axial ribs, between ribs transversal micro bands visible with SEM (Fig. 40). Teleoconch sculptured with axial oblique wrinkles more conspicuous in body whorl (Fig. 41); axial wrinkles of different thickness interrupted by spiral, elevated, undulated rows, where triangular translucent lamellae are inserted (Fig. 42). Lamellae lost, in abraded specimens without periostracum. Three major spiral rows on center of each whorl, 3 to 6 minor spiral rows in zigzag, continuous, separated by regular intervals between each major row ( Fig. 43 View FIGURES 43 – 46 ). From each minor row, grow axial micro folds departing towards central portion of whorl. Spiral undulating bands cutting the axial folds giving appearance of an irregular net ( Fig. 44 View FIGURES 43 – 46 ). Suture deep, crenulated ( Fig. 45 View FIGURES 43 – 46 ). Aperture sub ovate, parietal callus prominent, palatal and columellar extremities elevated. Fusion of palatal and parietal sides forming a pronounced incision. Aperture with broad peristome, slightly reflexed (Fig. 39). Columellar lamella wide concave with pronounced margins (similar to S. pyriformis ). Basal lamella perpendicular to peristome, variable inclination, doubles size than suprapalatal tooth. Suprapalatal tooth small oblique to peristome, concave in its dorsal side, wide margin.

Shell Measurements: Holotype: H: 25.5; D maj: 9; H ap: 8.3; D ap: 6. FML 802 (n=9): H: 23–24.4 (Median:23.8); D maj: 7.35–7.7 (Median: 7.5); H ap: 7–7.9 (Median: 7.35); D ap: 5.15–5.5 (Median: 5.35); Ang sp: 28.5º–34º (Median: 31.35º); Ang max: 127.5º–133º (Median: 130.1º). FML 195594 (n=5): H: 20.5– 22.4 (Median: 21.2); D maj: 7.2–8 (Median: 7.5); H ap: 7–7.4 (Median: 7.2); D ap: 5.2–5.8 (Median: 5.4); Ang sp: 29º–34º (Median: 32º); Ang max: 128º–138º (Median: 133.2º).

Digestive System: Jaw ( Fig. 46 View FIGURES 43 – 46 ) Color light brown lustrous consisting in 12 lateral plaques imbricate and two central plaques rectangular. Plaques sculptured with fine transversal lines. Inferior border of jaw with irregular outline due to projections of plaques. Radula with central tooth tricuspid, lateral teeth bicuspid, marginal teeth tricuspid.

Pallial System: Similar to S. doellojuradoi . Pallial gland enlarged, not arcuate.

Reproductive System ( Fig. 47 View FIGURES 47 – 49 ): Ovotestis consisting of three fan shaped bunches of acini, each acinus digitiform, ramified, orange homogeneous. Hermaphroditic duct located in third whorl around columella. Distal and proximal portion of hermaphroditic duct narrow. Fertilization pouch slim, 1/3 of albumen gland total length. Oviductal portion orange with darker spots irregularly distributed, not present at proximal portion. Prostatic portion granular, yellowish. Bursa copulatrix duct with distal portion enlarged, 1/3 longer than spermoviduct. Vagina 1/4 of penis total length, inner wall smooth with three pilasters sculptured with small granules, similar to S. doellojuradoi . Flagellum narrow ( Fig. 48 View FIGURES 47 – 49 ), 1/3 longer than epiphallus. Epiphallus short, tubular, 1/4 of penis total length. Penial gland short and triangular, within proximal portion of penis. Penial inner wall corresponding to area I with longitudinal irregular folds. Penial area II internally delimited by pilaster formed by overlapping lamella. Pilaster delimiting a quadrangular network area formed by irregular rows ( Fig. 48 View FIGURES 47 – 49 ). Pilaster extending from penial area II to V, laterally or centrally positioned. Inner wall of area III sculptured with rectangular pustules, in diagonal position. Area IV with numerous, irregular pustules; becoming less numerous towards area V. Distal portion of penial area V with longitudinal folds, semi undulated, separated by regular spaces. Penial sheath short, overlapping distal portion of penis. Retractor muscle thick and wide, inserted into area I of penis. Vas deferens surrounding retractor muscle at point of insertion of retractor muscle, running parallel to epiphallus ( Fig. 49 View FIGURES 47 – 49 ).

Habitat: Spixia tucumanensis lives under rocks and among roots and basal portions of small shrubs.

Distribution: Argentina, Tucumán Province. Area of distribution of the present species is part of the Chaco and Monte biogeographic area in Argentina delimited by Morrone (2006).

Remarks: Spixia tucumanensis is rather constant in its shell size but the subpyriform shape of the shell sometimes is not evident in some specimens. Parodiz (1941, 1942b) did not describe the structure of the periostracum formed by spiral rows and lamella inserted on them. He only mentioned a “surface with vestiges of spiral lines”. In specimens that have lost the periostracum, the spiral rows are absent and the body whorl does not show spiral grooves marked on the shell wall as it happens in S. martensii and S. pyriformis . The spiral rows of the periostracum in S. tucumanensis and in S. pyriformis are continuous and well marked when the periostracum is well preserved, whereas in S. martensii the rows are interrupted at irregular spaces. In the pallial system, the pallial gland is enlarged, not arcuate, as it is in the rest of the species of the complex. In the reproductive system, the penial gland is short and triangular, similar to S. doellojuradoi but different from the rest of the species in which the penial gland is rounded. The penial area I and V are similar to the other species. Areas II, III and IV show differences with the other species. Area II has a quadrangular net different from S. doellojuradoi and S. pyriformis where a circular net is present. In the area II of S. martensii this kind of net is not evident. In S. tucumanensis the penial area III, the pustules of the wall are rectangular and organized in diagonal position, different in shape from the rest of the species. In the present species´s penial area IV the pustules are similar in appearance to S. pyriformis but they differentiate from this in that the pustules are smaller and irregular in shape. This area in S. doellojuradoi and S. martensii is sculptured with rows V shaped, completely different to S. tucumanensis where pustules are present in this penial area.

Parodiz (1941) stated that the type locality of the present species is the “Margins of Salí River, near of Tucumán city” with no coordinate or any other precision. However, the area has changed considerably during the last decades with the margins of Salí River profoundly disturbed. Although an exhaustive search was done, neither dead nor living material of this species was found in the area.

Specimen Record: FML 82 (DM): Tucumán, Trancas dept. on the road from Tapia to Raco, 15/08/1946, P. Girard leg. FML 522 (DM): Tucumán, Trancas dept. on the road from Tapia to Raco, 900 m, 18/06/1967, W. Weyrauch leg. FML 802(DM): Tucumán, Trancas dept., Tapia 900 m, 14/02/1974, W. Weyrauch leg. FML 14774 (DAM): Tucumán, Trancas dept. on the road from Tapia to Raco, 945m, 26º 36’ 49”S 65º 21’ 16” W, 12/05/2005, M.G. Cuezzo & E. Salas Oroño leg. FML 195594(DM): Tucumán, Trancas dept. on the road from Tapia to Raco, 900 m, 18/06/1967 W. Weyrauch leg