Typhlonectes compressicauda (Duméril & Bibron, 1841), Dumeril & Bibron, 1841

Maciel, Adriano O. & Hoogmoed, Marinus S., 2011, Taxonomy and distribution of caecilian amphibians (Gymnophiona) of Brazilian Amazonia, with a key to their identification, Zootaxa 2984, pp. 1-53 : 38-41

Typhlonectes compressicauda (Duméril & Bibron, 1841)

Caecilia compressicauda Duméril & Bibron, 1841: 278 .

Typhlonectes obesus: Taylor, 1968: 253 ; Wilkinson, 1991: 307.

Typhlonectes compressicauda: Taylor, 1968 ; Moodie, 1978: 1005; Hoogmoed, 1979: 273; Frost, 1985: 640; Wilkinson, 1991:304; LaMarca et al., 2004; Neckel-Oliveira & Gordo, 2004: 165, 171; Wilkinson & Nussbaum, 2006: 71; Galatti et al., 2007: 93; Frost, 2008.

Nectocaecilia ladigesi Taylor 1968: 273 ; Taylor, 1970b: 859; Wilkinson, 1991: 307; Glaw & Franzen, 2006: 156.

Typhlonectes cunhai Cascon, Lima-Verde & Benevides Marques, 1991: 96 ; Wilkinson & Nussbaum, 2006)

Typhlonectes sp. 1 Bannermann, 2001: 164.

Diagnosis. Maximum known TL 800 mm ( Moodie, 1978). PA 75–88. Head slightly compressed. Dilated, broadly spatulate tooth crowns (more pointed in T. natans ; Wilkinson, 1991). Anteriorly tongue not completely attached to mandibular mucosa; two large narial plugs. AD 9–11. Terminal part of body triangular in cross-section, flat ventrally, ridged dorsally.

Description. TL 16–36.8 times (23.3 ± 4; n = 67) BW. Head slightly narrower than body and slightly laterally compressed. Nuchal grooves may be totally indistinct dorsally and ventrally but distinct laterally; no dorsal transverse groove on either collar. PA difficult to count, especially in posterior part of body of most of specimens, because of folds in loose skin (= pseudosecondaries of Nussbaum & Wilkinson, 1989). Primary annular grooves interrupted dorsally along most of body. PA ending anterior to vent. Unsegmented terminal shield posterior to vent; may be slightly compressed. Vent disk subcircular; AD 9–11 (10 ± 0.2; n = 103), one specimen had nine very clear denticulations, and six specimens had 11 denticulations; generally an approximately similar number in posterior and anterior edge of vent (e.g. five anterior, five posterior ones in MPEG 8006). Vent disk may be depressed and surrounded by fleshy folds of skin in both large males and females. Paired anal papillae present in only four of the 22 males analyzed in a sample of 98 specimens. Diminutive dermal scales may be present in posterior quarter of the body of some specimens ( Wake, 1975). Four series of teeth, all monocuspid, but strong variation in shape of teeth may occur, with a tendency to have a much dilated tooth crown in young ( Wilkinson, 1991). PMT maximally 52 ( Taylor, 1968) with no distinct variation in size, they may extend posteriorly of choanae as PPT. PPT maximally 48, smaller than other teeth. No diastema between PVT and PPT. DT maximally 60 ( Taylor, 1968), larger than PMT. ST at most 14, approximately same size as PPT.

Color. In life and preservative different tones of brown or blue. Color homogeneous along body, except paler around eyes and vent region.

Variation. Distinct sexual dimorphism in terminal region, females having a narrower and more pointed terminal tip. A single specimen (MPEG 4616) has nine regular anal denticulations, which is an uncommon condition in T. compressicauda , but characteristic for T. natans (from NW South America; Taylor, 1968). Geographic variation is not evident ( Table 13 ).

Typhlonectes compressicauda from Brazilian Amazonia.

continued next page Distribution. Brazil, Colombia, French Guiana, Guyana, and Peru ( Fig. 21 ) ( Taylor, 1968; Nussbaum & Hoogmoed, 1979; Duellman & Trueb, 1994; Lynch, 1999). Despite its presence in Guyana and French Guiana (only eastern part), it has not been reported from Suriname ( Nussbaum & Hoogmoed, 1979). This is a distribution pattern that can be observed also in several aquatic Amazonian reptiles [e.g. Melanosuchus niger (Spix, 1825) ] that reach the Guianas, and which is perhaps due to the absence of a direct connection between the rivers of Suriname with the Amazon drainage.

Natural history. This species is viviparous and gives birth to aquatic young. Some authors ( Wake 1970; Moodie, 1978; Exbrayat, 1983; Exbrayat & Delsol, 1985) report a markedly seasonal reproductive cycle. Murphy et al. (1977) provided observations on breeding behavior of T. compressicauda comparing it with that of another Typhlonectidae , Chthonerpeton indistinctum (Reinhardt & Lütken, 1862) .

Moodie (1978) found specimens in tunnels at water level about 30–60 cm deep in a bank of a river in Brazilian Amazonia with the tunnels spaced about 3–4 m apart, suggesting a high population density. Animals left tunnels at night to forage, mostly in shallow water; gut contents of 50 individuals included shrimps and other arthropods. Verdade et al. (2000) found insects, annelids, anuran eggs and vegetal matter in the guts of 18 young T. compressicauda . MPEG 7549 was encountered at 23:00 h in shallow water (10 cm deep) between grass, at the margin of a river with dead, fallen trees and grassland on its banks. Apparently this species can be abundant, often being well known to local fishermen. In the region of Belém, Brazil, it is not difficult to find specimens in native shrimp traps.

This species generally is considered aquatic, but Himstedt (1996; 1998), based on Moodie’s (1978) report, and on observations of Chthonerpeton indistinctum in an aquaterrarium, concluded that Typhlonectids possibly are not purely aquatic, but rather spending part of the time (daytime) in burrows on land, and night in the water, searching for prey. However, Gorzula & Señaris (1998) found Nectocaecilia petersi in Venezuela in water during day, and an active specimen crawling on the bank of a creek at night. In captivity T. compressicauda was observed to swallow the skin after shedding (F. Carvalho-Filho, pers. comm.).

Remarks. Wilkinson (1991) synonimized T. anguillaformis , T. obesus and Nectocaecilia ladigesi with T. compressicauda . Wilkinson & Nussbaum (2006) synonimized Typhlonectes cunhai with T. compressicauda . We have no reason to doubt these synonymies.

Figures

FIGURE 21. Distribution of Typhlonectes compressicauda. Open symbols represent data from literature; closed symbols specimens analyzed in this study. 1. Puerto Gaitán, Meta, Colombia (Lynch, 2006); 2. Leticia, Colombia (Duellman & Trueb, 1994); 3. Estação Ecológica de Mamirauá, Uarini, Amazonas; 4. Tapauá, Amazonas, Brazil; 5. Beruri, Amazonas, Brazil; 6. Manaus, Amazonas, Brazil; 7. Careiro, Amazonas, Brazil; 8. Rio Nhamundá, Faro, Pará, Brazil; 9. Type Locality, Cayenne, French Guiana; 10. Kaw and surroundings, French Guiana based on map of Lescure & Marty (2000) 11. Região dos lagos, Amapá, Brazil (Caramaschi & Pombal Jr., 2000); 12. Macapá, Amapá, Brazil; 13. Ilha de Marajó, Pará, Brazil; 14. Abaetetuba, Pará, Brazil; 15. Belém, Pará, Brazil; 16. Castanhal, Pará, Brazil; 17. Capitão Poço, Pará, Brazil; 18. Tomé-Açú, Pará, Brazil; 18. Tomé-Açú, Pará, Brazil.

Tables

TABLE 13. Morphometric (in mm) and meristic data (range, mean ± standard deviation and sample size in parenthesis) of

	Belém region	Macapá AP	Tapauá AM	Manaus region	Mamirauá AM	Pitinga AM	Faro PA
TL	128–610 278.2±137.6 (58)	210 (1)	140–159 148±8.1 (4)	122–460 243.6±109.9 (30)	205–330 250±69.4 (3)	143–163 152.6±10 (3)	330 (1)
HW	4.9–16.9 8.8±3.1 (58)	7.8 (1)	6.2–7.2 6.6±0.3 (5)	5.9–14.3 8.3±2.1 (33)	8.2–10 8.9±0.9 (3)	5.9–6.8 6.2±0.4 (3)	9 (1)
HL	7.9–19 12.3±3.5 (58)	11.2 (1)	9.1–10.4 9.3±0.5 (5)	8.5–19.7 11.5±2.8 (31)	10.9–14.7 12.2±2.1 (3)	8.7–9.8 9.1±0.6 (3)	13.4 (1)
HH	3.4–10.8 5.4±1.8 (58)	4.6 (1)		3.6–8.6 5.2±1.3 (31)	5.2–5.7 5.4±0.2 (3)	3.5–4.7 3.9±0.6 (3)	5.5 (1)
BW	5.5–28.4 10.6±6.2 (41)	10.3 (1)	9.9 (1)	5.4–21.9 21.1±4.7 (20)	9.6 (1)	6.2–7.6 (2)	15.6 (1)
BH	6.3–28.5 11.6±6 (42)	13.3 (1)	14.4 (1)	7.1–25.6 14.4±5.1 (20)	12.3 (1)	6.7–7.1 (2)	17 (1)
WNC	5.4–21.5 10.3±4.4 (44)	8.4 (1)	7.1–8 (2)	7.1–15.1 10.9±2.1 (16)	9–10.9 (2)	6.2 (1)	12.6 (1)
WTR	4.6–19.3 7.9±4 (43)	8.8 (1)	7.9 (1)	4.8–15 9.5±3 (18)	8.7 (1)	4.5–5.1 (2)	9 (1)
WV	2.9–12.1 5.4±2.4 (49)	4.9 (1)	5.9 (1)	3.5–11.9 7.4±2.3 (17)	5.3 (1)	3–3.5 (2)	10.6 (1)
EE	4.1–9.9 6.1±1.6 (58)	5.1 (1)	5–5.8 5.2±0.3 (5)	4–9.2 5.5±1.3 (31)	5.7–6.8 6.1±0.6 (3)	4.5–5.1 4.8±0.3 (3)	6.9 (1)
EN	2.3–8.8 3.9±1.3 (57)	3.2 (1)	2.7–3.6 2.9±0.3 (5)	2.3–5.6 3.4±0.9 (31)	3.4–4.2 3.7±0.4 (3)	2.7–3.3 2.9±0.3 (3)	4.3 (1)