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Fig. 3 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 3. Hemipenes of Eutrachelophis bassleri, new species. The distal nude section is greatly distensible, becoming hemispherical on eversion. Because of differential tissue expansion, the close-lying branches of the sulcus spermaticus diverge and acquire a centrifugal orientation, entering onto the nude dome from nearly opposite sides of the everted organ. A. Uneverted left hemipenis of AMNH R-55786 (paratype), opened by midventral incision. B. Everted right hemipenis in sulcate view, AMNH R-25193 (paratype; depiction of the manually everted organ). C. Same organ as in B, in asulcate view. D. Distal half of everted hemipenis showing appearance of the maximally inflated, mostly nude dome, from left to right: asulcate side, apex, and sulcate side. Left organ of TCWC 41424, paratype. (This organ previously had been manually turned inside out, but, because the base had been badly damaged, only the distal half was tied off and injected with petroleum jelly in an attempt to determine maximum inflation). Abbreviations: Folds, expansion folds; Mus, major retractor muscle; ND, nude dome; SB, a branch of the sulcus spermaticus; SS, sulcus spermaticus (proximal to bifurcation); Spic, densely spiculate area below and around base of nude dome; SpLg, large lateral and basal spines; SpSm, small spines on sulcate and asulcate faces.
Fig. 1 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 1. Eutrachelophis bassleri, new species. Dorsal and ventral views of adult specimens: A. AMNH R- 52926 (male holotype), from upper Río Pisqui, Peru. B. AMNH R-53473 (female paratype), from upper Río Utuquinia, Peru, near border with Brazil. The conspicuous nuchal markings are ''cream'' or ''yellow'' in life. Specimens shown life size.
Fig. 2 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 2. Heads of Eutrachelophis bassleri, new species. A, B. AMNH R-53473, adult female (369 mm total length), in dorsal and lateral view, ×3.9. C. TCWC 41425, juvenile male (160 mm total length), ×2.5. In addition to the white or yellow nuchal markings, the postocular extension of white or yellow labial color (B) is diagnostic of E. bassleri and its unnamed sister species (cf. fig. 4); the white preocular bar is present or absent in E. bassleri.
Map 1 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Map 1. Locality records for three species of Eutrachelophis, new genus, in western and middle Amazonia.
Fig. 26 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 26. Two small Panamanian snakes, genus Enulius— anatomically similar and apparently closely related—but recently separated generically on the basis of what appears to be extreme variation in the hemipenes (see text and fig. 27). A. Enulius flavitorques (Cope), with a yellow nape band (AMNH R- 109600, Canal Zone, Ancon). B. ''Enuliophis'' sclateri (Boulenger), with an enamel white head (KU 112619, San Blas, Camp Sasardí. Both photographed larger than life by C.W. Myers).
Fig. 8 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 8. Head of Eutrachelophis steinbachi (Boulenger) (UMMZ 60736), showing details of color pattern. The oblique alignment of the pale ocelli differentiates E. steinbachi from E. bassleri and its unnamed sister species (cf. figs. 2 and 4).
Fig. 16 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 16. Everted hemipenis of Mehelya poensis (Smith). (AMNH R-12053, left organ.) This is a slight, deeply forked hemipenis with long slender lobes and a very long retractor muscle that originates close to the tail tip. This organ divides at subcaudal 4, with the lobes terminating at about subcaudal 21 (an indistinct join between lobe and retractor); the two slips of retractor muscle fuse at subcaudal 29, but the long muscle continues posteriorly to a broad attachment between caudals 46–49, only 10 subcaudals before the terminal caudal spine.
Fig. 7 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 7. Eutrachelophis steinbachi (Boulenger), handheld preserved specimens. Upper. A specimen (NMW 23106) cited as ''syntypus'' by Tiedemann and Häupl (1980: 61) but not mentioned in Boulenger's (1905: 454) original description. Low- er. The syntype (BMNH 1946.1.21.63) designated lectotype in this paper (photograph courtesy of James R. Dixon).
Fig. 14. A in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 14. A. Echinanthera undulata (Wied). Vivid pale nuchal spots—similar to Eutrachelophis spp.— characterize some xenodontine (and dipsadine) snakes such as this Brazilian snake (AMNH R-119764). B. Taeniophallus bilineatus (Fischer). A distinct lateral line of whitish dashes emphasized by black edging characterize Eutrachelophis spp. and other xenodontines (and dipsadines) such as this Brazilian species (AMNH R-119769); the pale canthal line seen here is variably present in ''xenodontines,'' but does not occur in Eutrachelophis (photographs by C.W. Myers).
Fig. 25 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 25. Evolutionary loss of a bilobed hemipenis and a forked sulcus spermaticus, demonstrated by apparent sister species. A. Taeniophallus brevirostris (W. Peters) showing retention of weak bilobation (right lobe incompletely everted) and shortening of the left branch of the sulcus spermaticus (MZUSP 8484, left organ). B. T. brevirostris showing complete loss of bilobation and similar shortening of the left branch of the sulcus spermaticus (AMNH R-28799, right organ). C. Taeniophallus nicagus (Cope) showing complete loss of bilobation and complete loss of bifurcation in the now-single sulcus spermaticus, which extends from the base to one side of the apex (AMNH R-138683, right organ). D. T. nicagus, an uneverted hemipenis, showing the unbifurcated sulcus spermaticus that extends to the apex, where it is largely concealed by the close-pressed sulcus lips (MCZ 149545, left organ). The first three hemipenes were manually and fully everted (except for one resistant lobe in A), but they probably are not completely expanded as is commonplace with eversions made from preserved specimens. Not to same scale.
Fig. 30 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 30. Xenodon rabdocephalus, sensu lato (these specimens tentatively assigned to X. angustirostris W. Peters). Dorsal and ventral views of young specimens from western coastal Colombia (Quebrada Guanguí, Dept. Cauca, 100–200 m. A. AMNH R-109777 subadult female. B. AMNH R-109776 juvenile). See also figure 31 for specimens from Panama and Venezuela.
Fig. 24 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 24. Inter- and intrapopulational hemipenial variation in Rhadinaea decorata (Günther). A. Short bulbous hemipenis, 7 subcaudals long, Veracruz, Mexico (TCWC 21391, right organ). B. Long slender hemipenis, 11 subcaudals long, Costa Rica (USNM 120832, right organ). Geographic variation is complex, comprising lengths of 5–8 subcaudals in Mexico and 6–14 subcaudals in Costa Rica through Panama. Field eversions, drawn to same scale, from Myers, 1974: 74–75.
Fig. 18 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 18. Hemipenis of Xenodon rabdocephalus, sensu stricto. Right retracted organ of AMNH R-3609, from Bahia, Brazil; designated lectotype herein). Abbreviations: AD, apical disc; ADW, apical disc wall or lip; Mus, dorsal and ventral slips of the major retractor muscle; SB, branch of sulcus spermaticus; SS, sulcus spermaticus below fork; STB, smooth terminal basin.
Fig. 10 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 10. Continued. trigeminal nerve; Vrp, foramen for retractor pterygoideus ramus of trigeminal nerve; V2, foramen for maxillary ramus of trigeminal nerve; V2VIIp, foramina for combined maxillary ramus of trigeminal nerve and palatine ramus of facial nerve (5 orbitopalatine nerve); V3VII, foramen for mandibular ramus of trigeminal nerve and facial nerve; VIIp, foramina for palatine ramus of facial nerve; IX, foramen for glossopharyngeal nerve; X, foramen for vagus nerve; XII, foramina for hypoglossal nerve.
Fig. 11 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 11. Skull of Eutrachelophis steinbachi (Boulenger) (AMNH R-125695), ×7.7. Abbreviations: Same as for figure 10, but here repeated only for nerve and venous foramina. With only one skull each of E. bassleri and E. steinbachi, no significance can be attached to any slight differences in positioning of these foramina, which are so labile that even the left and right sides of the same skull may sometimes differ.
Fig. 22 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 22. Illustration (from Pope, 1941: 251), showing copulatory adjustment between hemipenis (left) and female cloaca (right) of Liophis poecilogyrus, as seen by dissection after the snakes had been killed while mating. Pope commented: ''The ventral body wall of the female has been bisected and its halves spread apart to expose the interior of the cloaca, from which the turgid hemipenis was removed. The exposed side of the latter lay against the dorsal wall of the cloaca so that each sulcus spermaticus opened at the orifice of an oviduct.'' Species of Liophis have an apical disc on each hemipenial lobe (as in fig. 17A), which should confine the flow of seminal fluid to the opening of the oviduct; in this case there may have been a slight postmortem retraction of the discs. The area labeled ''ridge'' in this figure corresponds to the apical disc itself, which contains the terminus of the sulcus spermaticus.
Fig. 23 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 23. Illustration (after Inger and Marx, 1962: 36) showing intraspecific variation in the female cloaca of Calamaria lumbricoidea. Diagrammatic ventral views, with intestine cut and reflected. A. Bulbous cloaca. B. Cardioid type. C. Bilobed type. D. Bilobed type with ventral wall removed.
Fig. 29 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 29. The African genus Prosymna includes examples of extreme hemipenial diversity. A. Prosymna ambigua bocagii Boulenger, a snake with a slender, single (unforked) hemipenis longer than the tail when everted. Drawing of AMNH R-12145, reproduced from Schmidt (1923: 89). B. Same specimen as above, with tail opened, showing complex ''accordion'' folding of the uneverted contralateral hemipenis. The retractor muscles originate threadlike at the very tip of the tail, both with a small Z-shaped fold toward the hemipenis. Notice at the bottom side that the everted right hemipenis has the tip broken off. Inset at top: Greatly enlarged view of the folded part of the inverted hemipenis. Inset at lower right: Enlarged view of the tip of the broken right hemipenis, showing ridgelike structures at the terminus. C. Prosymna sundevallii (A. Smith) hemipenes showing peculiar anastomosing flouncing, from Broadley (1980: pl. IIA). Abbreviations: AG, presumed small anal gland; HP, hemipenis; Mus, termini of left and right retractor muscles; MusZ, large Z-shaped fold in left retractor muscle; SS, sulcus spermaticus.
Fig. 28 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 28. The deeply divided, exceedingly long-lobed hemipenis of Pseudaspis cana (Linnaeus) (AMNH R-49948, right hemipenis). The contralateral (left) organ of this snake originates near the end of the tail at subcaudal 44 (there are 55 subcaudals total); although the left organ was partially everted, its retractor muscle retained a series of sinuous folds that seemed to straighten somewhat after being freed from membranous tissue. The branches of the sulcus spermaticus orbit each lobe several times; the sulcus orientation is ''centrifugal-orbital'' following the classification proposed herein. (The orbiting nature of the sulcus is not clearly evident in a partially everted organ illustrated by Cope, 1895: pl. 24, figs 9, 9a.)
Fig. 21 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters
Fig. 21. Distinct hemipenial capitula (heads) with and without capitation. A. Rhadinaea taeniata (Peters). Retracted and everted views showing a capitate capitulum set off by a well-developed overhang that is interrupted only by entrance of the sulcus spermaticus (UMMZ 121522, left retracted and right everted organs; from Myers, 1974: 107, fig. 23A, B). B. Compsophis infralineatus (Günther). Sulcate and three-quarters views of a well-developed capitulum lacking capitation (MZC 181153, everted; from Cadle, 1996b: 75, fig. 17, as Geodipsas). The capitula are ornamented with calyces in A and with small spines in B. (See also fig. 3 for a distinct noncapitate capitulum that is distally nude and proximally spiculate.)
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