Santiago J. Sánchez-Pacheco

Descripción de las larvas de dos centrolénidos (Anura: Centrolenidae) del noroccidente de la Cordillera Oriental, Colombia

Se describen las larvas de dos especies de la familia Centrolenidae (Hyalinobatrachium ibama y Cochranella daidalea) procedentes del flanco occidental de la cordillera Oriental en el departamento de Norte de Santander, Colombia. En la descripcion de las larvas, ademas de las caracteristicas morfologicas tradicionales, se incorporaron nuevos elementos de juicio como la longitud del tubo cloacal, la forma del rostro, el patron de color y la posicion del espiraculo, los cuales resultaron ser informativos y muy utiles en la diferenciacion de las especies. Se proporciona una discusion acerca de la validez taxonomica de algunos de los caracteres morfologicos empleados usualmente en las descripciones y comparaciones de los renacuajos de la familia Centrolenidae.

A New Species of Riama from Ecuador Previously Referred to as Riama hyposticta (Boulenger, 1902) (Squamata: Gymnophthalmidae)

ABSTRACT We describe Riama crypta, new species, from the western slopes of the Cordillera Occidental, Ecuador. This taxon was formerly referred to as Riama hyposticta, a rare species described on the basis of an adult male from northern Ecuador and here recorded from southwestern Colombia. The new species differs principally from Riama hyposticta by an incomplete superciliary series, formed just by the anteriormost superciliary scale (superciliary series complete in R. hyposticta, formed by five or six scales), no nasoloreal suture [= loreal absent] (complete [= loreal present] in R. hyposticta), distinct dorsolateral stripes at least anteriorly (scattered brown spots dorsally without dorsolateral stripes in R. hyposticta), and ventral coloration composed of small cream or brown spots or longitudinal stripes (dark brown with conspicuous transverse white bars and spots). Additionally, we document the presence of distal filiform appendages on the hemipenial lobes of both species.

A New “Microteiid” Lizard (Squamata: Gymnophthalmidae: Riama) from Southwestern Colombia

Abstract I describe a new species of Riama from the Pacific versant of the Andes in extreme southwestern Colombia. Among the species of Riama, the new species most resembles R. vieta, with which it shares rugose dorsal and ventral scales. Unlike R. vieta, the new species has three postoculars and males lack heavy black spots dorsally and black bands ventrally. Males of the new species have seven to eight femoral pores per leg (total number 14–15) and two scales between the femoral pores (anterior cloacal plate scales paired).

The advertisement calls of three hylid frogs from Hispaniola

Abstract In this study, we provide detailed descriptions of the previously unknown advertisement calls of Osteopilus dominicensis and Hypsiboas heilprini, as well as a complete redescription of that of O. pulchrilineatus, three of the four hylid frogs known from the Caribbean island of Hispaniola. The call of O. dominicensis is composed of a single multi-pulsed note with a mean dominant frequency of 2058 Hz. In contrast, the call of O. pulchrilineatus consists of two different pulsed notes (the second repeated many times in one call) with a mean dominant frequency of 2950 and 2060 Hz, respectively. The call of H. heilprini, in turn, is a trill consisting of multi-pulsed notes (emitted in a consecutive series) with a mean dominant frequency of 1738 Hz. We compare these three calls to those of closely related species.

Lizards of the Genus Riama (Squamata: Gymnophthalmidae): The Diversity in Southern Ecuador Revisited

ABSTRACT. Following examination of recently collected and older specimens of Riama from southern Ecuador, we report morphological variation in R. vespertina and modify the species diagnosis and description accordingly; furthermore, we describe two new species, comment on additional diversity of the genus in this region and discuss some character-states, specially dorsal scale relief (specifically striated and keeled conditions). We provide an identification key to the species of Riama occurring in southern Ecuador.

Lectotype designation and redescription of the Gymnophthalmid lizard Riama columbiana (Andersson, 1914) with notes on the type Locality

Con base en los sintipos y material adicional se redescribe Riama columbiana, un lagarto gymnophthalmido de los andes colombianos poco conocido. Un lectotipo es designado y su probable proveniencia discutida. Ademas, se presentan datos sobre la distribucion y la historia natural de la especie.

New Endemic Species of Riama (Squamata: Gymnophthalmidae) from Northern Colombia

Abstract A new endemic species of gymnophthalmid lizard of the genus Riama is described from the Cordillera Occidental of northern Colombia. The new species differs from all known Riama by pholidosis, hemipenial morphology, and color pattern. The four known endemic Colombian species, Riama columbiana, Riama laevis, Riama stellae, and Riama striata, occur in different montane forests and are not known to be sympatric with the new species. The new species most resembles R. laevis from the Cordillera Occidental of the Colombian Andes, but it differs in having 15 longitudinal scale rows, 21–23 transverse scale rows in males and 22 in females, and limbs that do not overlap or just touch when adpressed against the body.

Phylogeny of Riama (Squamata: Gymnophthalmidae), impact of phenotypic evidence on molecular datasets, and the origin of the Sierra Nevada de Santa Marta endemic fauna

Riama is the most speciose genus of the Neotropical lizard family Gymnophthalmidae. Its more than 30 montane species occur throughout the northern Andes, the Cordillera de la Costa (CC) in Venezuela, and Trinidad. We present the most comprehensive phylogenetic analysis of Riama to date based on a total evidence (TE) approach and direct optimization of molecular and morphological evidence. Analyses use DNA sequences from four loci and 35 phenotypic characters. The dataset consists of 55 ingroup terminals representing 25 of the 30 currently recognized species of Riama plus five undescribed taxa, including an endemic species from the Sierra Nevada de Santa Marta (SNSM) in Colombia, and 66 outgroup terminals of 47 species. Analysis results in a well‐supported hypothesis in which Riama is polyphyletic, with its species falling into three clades. The Tepuian Anadia mcdiarmidi nests within one clade of Riama, and the recently resurrected Pantodactylus nests within Cercosaura. Accordingly, we propose a monophyletic taxonomy that reflects historical relationships. Analysis of character evolution indicates that the presence/absence of prefrontals—a cornerstone of the early genus‐level taxonomy of cercosaurines—is optimally explained as having been plesiomorphically present in the most recent common ancestor of Cercosaurinae and lost in that of the immediately less inclusive clade. Multiple independent reversals to present and subsequent returns to absent occur within this clade. To evaluate the impact of phenotypic evidence on our results, we compare our TE results with results obtained from analyses using only molecular data. Although phenotypic evidence comprises only 1.2% of the TE matrix, its inclusion alters both the topology and support values of the clades that do not differ. Finally, current phylogenetic evidence reveals a SNSM–CC–Trinidad–tepuis biogeographical link. We hypothesize that an ancient connection facilitated the exchange of species between the SNSM and the CC.

On the use of median‐joining networks in evolutionary biology

Median‐joining (MJ) was proposed as a method for phylogeographical analysis and is enjoying increasing popularity. Herein, we evaluate the efficacy of the approach as originally intended. We show that median‐joining networks (MJNs) are theoretically untenable for evolutionary inference, and that confusion has afflicted their use for over 15 years. The approach has two obvious shortcomings: its reliance on distance‐based phenetics (overall similarity instead of character transformations) and the lack of rooting (no direction or history). Given that evolution involves both change and time, and the absence of rooting removes time (ancestor–descendant relationships) from the equation, the approach cannot yield defensible evolutionary interpretations. We also examine the impact of MJ analyses on evolutionary biology via an analysis of citations and conclude that the spread of MJNs through the literature is difficult to explain, especially given the availability of character‐based analyses.

Hylid Tadpoles from the Caribbean Island of Hispaniola: Ontogeny, Description and Comparison of External Morphology

Abstract The island of Hispaniola (Dominican Republic and Haiti) is home to four endemic species of treefrogs: Hypsiboas heilprini, Osteopilus dominicensis, O. pulchrilineatus and O. vastus. These species occur sympatrically over large areas below 1,850 m elevation and are commonly encountered together. We redescribe the external larval morphology of O. dominicensis, O. vastus, and Hybsiboas heilprini, and describe the tadpole of O. pulchrilineatus for the first time based on laboratory-reared specimens representing stages from early—late metamorphosis. Some tadpoles were raised to adults in order to confirm species identity. We document intraspecific variation in labial tooth-rows formulas, report ontogenetic changes in coloration, compare tadpoles of related species, and provide an identification key to the hylid tadpoles of Hispaniola. Hispaniolan hylid tadpoles inhabit fast-running streams or pools. Whereas the lotic larvae of O. vastus and H. heilprini exhibit characteristics commonly associated with flowing water (robust body with strong tail musculature, small to medium fins, relatively enlarged oral disc, increased number of labial tooth rows, and complete marginal papillae), the lentic tadpoles of O. dominicensis and O. pulchrilineatus are characterized by morphological adaptations to ponds (medium-sized body and tail musculature, high fins, small oral disc, fewer number of labial tooth rows and incomplete marginal papillae). Consequently, the tadpole of O. vastus is more similar to that of H. heilprini than it is to its congeners.