Pseudopaludicola falcipes, (Hensel, 1867) (Hensel, 1867)

Laufer, Gabriel & Barreneche, Juan M., 2008, Re-description of the tadpole of Pseudopaludicola falcipes (Anura: Leiuperidae), with comments on larval diversity of the genus, Zootaxa 1760 (1), pp. 50-58 : 52-54

Tadpole description

The specimen illustrated (ZVC-B 11287; Fig. 1 ), collected in Minas de Corrales, Rivera, is at Gosner stage 37 and has the following measurements in mm: BL = 7.70, TAL = 13.41, TL = 21.11, IND = 0.99, IOD = 2.67, MTH = 3.71, TMH = 2.08, and TMW = 1.60. Table 1 summarizes the measurements of tadpoles in different stages.

The larvae of P. falcipes have a TL of 7.61 ± 0.88 mm (mean ± standard deviation). They show a depressed body (body width/ body height = 1.3), with oval shape in dorsal view. The snout is rounded in lateral and dorsal view. The eyes are mid-sized, not having important protrusion. They are positioned dorsally and oriented dorsolaterally. In ventral view the eyes are not visible. The IND is about 39 % of the IOD. The rounded external nares are moderate in size, directed dorsally, and equally distant from the snout tip and the eyes. The spiracle is single, sinistral, positioned laterally, and posterodorsally oriented. It is visible in dorsal view, and its inner wall is free from the body wall. The spiracular opening is oval and situated at mid body height, facing posteriorly. The vent tube is short, tubular and medial. It is associated with the ventral fin, and its opening is directed medially. The TAL is about 64 % of the TL. The dorsal fin originates near the dorsal tail body junction, but begins to expand at the middle of the tail length. The ventral fin originates at the body terminus and does not expand. The MTH is higher than body height and is located at the middle of the tail. The tail tip is pointed ( Fig 1 ).

The relaxed oral disc has elliptical shape and an anteroventral location. All but its anterior margin are free from the body wall. The upper labium is a continuation of the snout (sensu Altig & McDiarmid 1999). The oral disc is laterally emarginate, and lined by a single row (uniserial) of rounded pointed marginal papillae, which are not pigmented. The marginal papillation is interrupted, forming a wide anterior gap and three posterior narrow gaps. The posterior labium has one central gap with two lateral ones. The central gap is a small papillation interruption in the center, more or less coinciding with the position of the lower labial tooth row 3 (Fig 2). Submarginal papillae are absent. The jaw sheaths are finely serrated and keratinized along nearly their entire width. The upper sheath is arc-shaped, with long lateral processes extending well beyond the lower jaw. The lower sheath is V-shaped.

The labial teeth row formula and balance value are as follows: LTRF = 2(2)/3, BV = -1. length of teeth rows: A1 = 1.2 mm, A2 = 1.1 mm, gap of A2 = 0.5 mm; P1 = 1.0 mm, P2 = 0.9 mm, P3 = 0.2 mm. The medial gap present in the A-2 tooth row shows an inverted U-shaped depression. P-2 presents a quite narrow break, which is not considered a gap in the LTRF as it has no physical break at the tooth ridge, (sensu Altig & McDiarmid 1999). P-3 is exceptionally short, lying at the medial part of the posterior labium in a short ridge, with lateral marginal papillae. Labial teeth have a spoon-shaped head, with four to six terminal cups, and are arranged in uniserial mode.

In life, the body is dark brown with a reticulated and spotted tail, exhibiting pink-coloured intestinal coils. The intestinal spiral is clearly visible through the abdominal wall. In preservative, the body is black, and it is darker between the eyes and in the tail muscles in dorsal view. Intestinal coils are visible laterally and ventrally. Both fins have almost no pigmentation, and tail musculature has reticulate spots with extensions to the fins.

Comparisons with the tadpole of P. boliviana

The results of the PCA are given in figure 3. The first factor explains 79.95 %, and the second explains 11.86 % of the total variation. The first component shows a differentiation mainly in body size. The less developed specimens of P. boliviana are found on the right. The second factor exhibits a differentiation between the two tadpole species. The variables that have important incidence in those differences are body width at nostrils (BWN), fronto-nasal distance (FN) and narial-ocular distance (NO). BWN and FN are shorter, and NO is longer in P. falcipes . To summarize, the examination of factor loadings indicates that in addition to its larger size, the P. falcipes tadpole is morphologically differentiated from the P. boliviana tadpole, in that it has a narrower and shorter snout, and a greater distance from eyes to nostrils.

Figures

FIGURE 1. Dorsal (a) and lateral (b) views of Pseudopaludicola falcipes tadpole, ZVC-B 11287 from Rivera, Uruguay. Gosner stage 37. Scale line: 5 mm.