70 (3): 291 – 304 © Senckenberg Gesellschaft für Naturforschung, 2020. 2020 Constrictores Oppel, 1811 – the available name for the taxonomic group uniting boas and pythons Georgios L. Georgalis 1, 2, * & Krister T. Smith 3, 4 1 Dipartimento di Scienze della Terra, Università di Torino, Via Valperga Caluso 35, Torino, 10125, Italy — 2 Department of Ecology, Labora- tory of Evolutionary Biology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Bratislava, 84215, Slovakia — 3 Department of Messel Research and Mammalogy, Senckenberg Research Institute and Natural History Museum, Senckenberganlage 25, Frankfurt am Main, 60325, Germany — 4 Faculty of Biological Sciences, Institute for Ecology, Diversity and Evolution, Max-von-Laue- Straße 13, University of Frankfurt, 60438 Frankfurt am Main, Germany — * Corresponding author; [email protected] Submitted April 25, 2020. Accepted June 17, 2020. Published online at www.senckenberg.de/vertebrate-zoology on June 26, 2020. Published in print on Q3/2020. Editor in charge: Uwe Fritz Abstract Recent advances in the phylogenetic relationships of snakes using both molecular and morphological data have generally demonstrated a close relationship between boas and pythons but also induced nomenclatural changes that rob the least inclusive clade to which both belong of a name. This name would be tremendously useful, because it is the least inclusive group to which a large number of fossil boa-like or python-like taxa can be assigned. Accordingly, an update of higher-level nomenclature is desirable. We herein provide an overview of all the names that have historically been applied to boas and pythons. We show that the earliest name for the supra-familial group encompass- ing boas and pythons is Constrictores Oppel, 1811. We herein revalidate it as an order-group name below Alethinophidia Nopcsa, 1923 and provide a phylogenetic defnition of it to encompass the modern concepts of Booidea and Pythonoidea. We provide emended diagnoses for Constrictores, Booidea, and Pythonoidea based on recent morphological data-sets. Key words Booidea, nomenclature, Pythonoidea, Serpentes. Introduction Boas and pythons are among the most well known snakes. semblages throughout the Paleogene in North America They comprise the largest forms, both extinct and extant and Europe, and achieved a considerable species richness (MURPHY & HENDERSON, 1997; HEAD et al., 2009), and and diversity, with a variety of sizes and habits (RAGE, have fascinated humans at least since Antiquity (SCHNEI­ 1984; SZYNDLAR, 1991; HEAD et al., 2009; GEORGALIS & DER, 1821). They have a broad geographic distribution, SCHEYER, 2019). Their fossil record comprises primarily covering almost all continents except Antarctica, being vertebrae and, more rarely, isolated skull bones (e.g., GIL­ found even in remote oceanic islands (WALLACH et al., MORE, 1938; RAGE, 1984; HOLMAN, 2000; SZYNDLAR & 2014). Although many species are widely distributed, RAGE, 2003; SMITH, 2013; GEORGALIS & SCHEYER, 2019), the range of other species is rather confned geographi- although complete, articulated skeletons have been found cally. Especially the latter species are increasingly in in certain Konservat-Lagerstätten, and even rare mum- need of conservation efforts (e.g., REYNOLDS & HENDER­ mifed specimens with scales have been recovered (FIL­ SON, 2018); one of them, Bolyeria multocarinata (Boié in HOL, 1877; ROCHEBRUNE, 1884; SMITH & SCANFERLA, 2016; Boié, 1827) went extinct in historical times, as recently SMITH et al., 2018; SCANFERLA & SMITH, 2020). as the 1980s (DAY, 1989; WALLACH et al., 2014). They Recent advances in snake systematics based on DNA have an extensive fossil record, dominating snake as- sequence data, coupled with novel interpretations of ISSN 1864-5755 | eISSN 2625-8498 | DOI: 10.26049/VZ70-3-2020-03 291 Georgalis, G. L. & Smith, K. T.: Constrictores Oppel, 1811 – the available name for the taxonomic group uniting boas and pythons morphology and skeletal anatomy, have lead to the rec- Daudin, 1803b. DUMÉRIL (1805), however, did not place ognition of boas and pythons as distinct superfamily-lev- Eryx (misspelled by him as Erix) into “boas” but rather el taxa (e.g., VIDAL et al., 2007; VIDAL & HEDGES, 2009; treated it as distinct. The same author, nevertheless, in- BURBRINK & CROTHER, 2011; REYNOLDS et al., 2014). Di- cluded “boas” and Erix in a higher, formal, group, which vergence dates among boas and pythons are estimated he named Hétérodermes, that also included a number of to have occurred as early as the Paleocene or the Late other snake groups (DUMÉRIL, 1805). Cretaceous (HEAD, 2015; HSIANG et al., 2015; ZHENG & OPPEL (1811a, b) applied the name Constrictores, in WIENS, 2016). The content of Booidea as a superfamily two different publications during the same year, to en- has been restricted (PYRON et al., 2014) to Neotropical compass only the genera Boa and Eryx. Although the boas (Boidae), American dwarf boas (Ungaliophiinae), genera Python Daudin, 1803b, and Eryx Daudin, 1803d, the Rainbow Boa and rubber boas (Charininae), the had been already established prior to OPPEL’s (1811a, b) Calabar Burrowing Python (Calabaria reinhardtii), the works, the latter author mentioned Eryx but not Python. In Malagasy boas (Sanziniidae), the Old World sand boas OPPEL’s (1811a:383; 1811b:58) concept of Boa, however, (Eryx [including Gongylophis]), and the Pacifc Island besides the mentioned species in his text, he also inserted boas (Candoia). Pythonoidea, in turn, encompasses Old “etc.”, thus making clear that he did not intend to list all World pythons (Pythonidae), sunbeam snakes (Xenopel- known taxa. Notably, he also listed the species Boa regia tis) and the Mexican Burrowing Python (Loxocemus Shaw, 1802 (currently Python regius; WALLACH et al., bi color). Boa- and python-like fossils, the majority of 2014). It thus appears that OPPEL (1811a, b) intended his which are known exclusively from vertebrae, frequently Constrictores to encompass all large taxa recognized as cannot be assigned with confdence to the boa or python booids and pythonoids today; furthermore, he specifcal- clades, and a term is now lacking for that higher-level ly excluded aniliids (which he placed in Tortrix Oppel, clade (BURBRINK et al., 2020) comprising both (e.g., 1811b) from his Constrictores. The name Constrictores GEORGALIS & SCHEYER, 2019). The question thus arises, was subsequently used by FISCHER VON WALDHEIM (1813), what should be the name for the clade uniting boas and who, however, expanded the denoted group to include pythons? We demonstrate that there is in fact an avail- the hydrophiine elapids Platurus Latreille in Sonnini and able name for this group and we accordingly revalidate Latreille, 1801 (i.e., Laticauda Laurenti, 1768) and Hy- and redefne it here. drophis Latreille in Sonnini and Latreille, 1801. RAFINESQUE (1815) applied the name Aplepia to en- compass Boa, Python, Eryx, and Corallus, as well as Taxonomic history the peculiar homalopsid genus Erpeton Lacépède, 1801. RAFINESQUE (1815:77) united these genera into Aplepia on the basis of their shared presence of “[u]n seul rang Several available names in the old literature have been de plaques sous la queue ou le corps” [a single row of established to denote the taxonomic entity comprising plates underneath the body]; according to his taxonomic boas and pythons. Many early workers simply assigned scheme, Aplepia was the counterpart of Diplepia (includ- all boas to the genus Boa Linnaeus, 1758 (e.g., LINNAEUS, ing Coluber and certain other colubrids, but also the elap- 1758; BODDAERT, 1783; GMELIN, 1789; SEETZEN, 1796; id Acanthophis) and both of them together constituted the LINK, 1807); pythons were instead referred to “couleu- family Colubrinia, which in turn belonged to the subor- vres” (e.g., LACÉPÈDE, 1789) or even formally to the der Heterodermia. genus Coluber Linnaeus, 1758 (e.g., LINNAEUS, 1758; CUVIER (1817) placed boas in their own group, termed GMELIN, 1789; BONNATERRE, 1790; SHAW, 1802). Others Boas, subdivided into “Boas propres”, Erix (sic), and Er- assigned the then-known species only to the genera Boa, petons (including Erpeton), whereas he placed pythons Python Daudin, 1803b, and Eryx Daudin, 1803d, but did (his Pythons) along with colubrids in a different group, not provide any higher group name (e.g., DAUDIN, 1803b, Couleuvres. The same author subsequently kept practi- d). Schneider (1801) placed several boas and pythons in cally the same taxonomic arrangement, with his Boas be- the genus Boa, but still kept Python molurus (Linnaeus, ing distinct from his Pythons, the latter still pertaining to 1758) in Coluber, and he treated “erycine” species as Couleuvres (CUVIER, 1829). members of Anguis Linnaeus, 1758 (note that in this pa- MAYER (1824) created the name Phaenopoda, denot- per we use the term “erycine” in quotes, because molecu- ing the presence of “spur-like” hind-limb rudiments in lar and combined phylogenetic analyses have universally these snakes, to encompass Boa, Python, and Eryx, as held the taxon Erycinae sensu RAGE [1984] to be poly- well as Tortrix (i.e., aniliids). That name was later dis- phyletic). In a similar vein, LATREILLE (1804), although he cussed by DUMÉRIL & BIBRON (1844; as “Phénopodes”), distinguished boas and pythons, included both in Colu- but curiously the name Phaenopoda was not mentioned at berini, along with the majority of snake genera. DUMÉRIL all in the detailed catalog of BOULENGER (1893). (1805) used the (apparently