Pelomedusa galeata
Creators: name: Petzold, Alice
name: Vargas-Ramírez, Mario
name: Kehlmaier, Christian
name: Vamberger, Melita
name: Branch, William R.
name: Preez, Louis Du
name: Hofmeyr, Margaretha D.
name: Meyer, Leon
name: Schleicher, Alfred
name: Široký, Pavel
name: Fritz, Uwe
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Reptilia
Testudines
Pelomedusidae
Pelomedusa
Pelomedusa galeata

description: Pelomedusa galeata (Schoepff, 1792)
1792 Testudo galeata Schoepff —Restricted type locality (Hewitt 1935): environs of Cape Town, South Africa; lectotype (Fritz et al. 2014): Biological Museum of Lund University, ZMUL 6481 (Fig. 3 bottom in Fritz et al. 2014)
1835 Pentonyx capensis Duméril & Bibron —Restricted type locality (by lectotype designation, Fritz et al. 2014): Cape of Good Hope, South Africa; lectotype (Fritz et al. 2014): Muséum National d’Histoire naturelle, Paris, MNHN 9506 (Fig. 4 in Fritz et al. 2014)
1863 Pelomedusa nigra Gray —Type locality: Natal, South Africa; lectotype (Fritz et al. 2014): The Natural History Museum, London, BMNH 1849.1.30.27 (Fig. 6 top in Fritz et al. 2014)
1935 Pelomedusa galeata devilliersi Hewitt —Type locality: Besondermeid, Steinkopf, Northern Cape, South Africa; holotype: Port Elizabeth Museum, PEM R 14962 (Fig. 7 bottom in Fritz et al. 2014)
1935 Pelomedusa galeata orangensis Hewitt —Type locality: Kimberley neighbourhood (?), Northern Cape, South Africa; holotype: McGregor Museum, Kimberley, lost (Fig. 4 of Plate XXXII in Hewitt 1935)
Diagnosis: Large-sized, often dark-coloured helmeted terrapins with an exceptional maximum straight carapacial length of 32.5 cm (Hewitt 1935, discussed in Branch et al. 1990). However, the normal shell length of adult terrapins is around 26 cm. Pectoral scutes always with broad or very broad contact at plastral midseam. In approximately 50% of all terrapins two small temporal scales present on each side of head, the others having one large undivided temporal scale. Two small barbels below chin. Soft parts dorsally darker than ventrally. Carapace and plastron of adults often mainly or entirely dark. However, in the western and northwestern parts of the range adults may be light-coloured with mainly or entirely yellow plastra. Pelomedusa galeata differs from all other Pelomedusa species except P. subrufa sensu stricto by the presence of cytosine (C) instead of adenine (A) or guanine (G) at position 148, by the presence of guanine (G) instead of adenine (A) at position 159, by the presence of cytosine (C) instead of thymine (T) at position 167, and by the presence of guanine (G) instead of adenine (A) or thymine (T) at position 343 of the 360-bp-long reference alignment of the 12S rRNA gene (Supporting Information). In addition, P. galeata differs from all other Pelomedusa species except P. subrufa sensu stricto (and possibly P. gehafie, P. kobe and candidate species B, in which the respective character states are unknown) by the presence of thymine (T) instead of cytosine (C) at position 26 and by the presence of cytosine (C) instead of thymine (T) at position 38. Pelomedusa galeata differs from P. subrufa sensu stricto by the presence of cytosine (C) instead of thymine (T) at positions 60 and 191, by the presence of thymine (T) instead of cytosine (C) at positions 117 and 298, by the presence of adenine (A) instead of thymine (T) at position 169, by the presence of guanine (G) instead of adenine (A) at positions 180 and 233, by the presence of adenine (A) instead of guanine (G) at positions 223, 226 and 296, by the presence of cytosine (C) instead of adenine (A) at position 280, and by the presence of guanine (G) instead of thymine (T) or cytosine (C) at position 289.
Distribution: South Africa (Eastern Cape, Free State, Gauteng, KwaZulu-Natal, North West, Northern Cape, Western Cape; Vargas-Ramírez et al. 2010; Fritz et al. 2014; this study).
Remarks: Pelomedusa galeata corresponds to mtDNA lineage IX of Vargas-Ramírez et al. (2010). It is one of the two southern species of Pelomedusa which constitute together a weakly supported clade based on phylogenetic analyses of mtDNA (Fig. 1).
According to phylogenetic analyses, P. galeata is composed of three distinct clades, one being represented by many samples from most of South Africa and two represented by only one and three samples, respectively (Fig. 1). However, the clade represented by only one sample (MTD T 5484, Swellendam District, Western Cape) is questionable. For MTD T 5484 are cyt b and ND4 sequences available, published in Vargas-Ramírez et al. (2010). The cyt b sequence is identical with or closely resembles those of the widely distributed South African clade. The ND4 sequence is highly distinct and identical to the ND4 sequence of another sample from the same province (MTD T 5897, Chelance, Western Cape), which is placed together with two other samples in the second small clade. Thus, it is evident that the distinct phylogenetic position of MTD T 5484 is an artefact caused by erroneously concatenated cyt b and ND4 sequences of two different terrapins.
Yet, if MTD T 5484 is disregarded, there still remain two deeply divergent clades within P. galeata which are unambiguous. Their average uncorrected p distances for the 12S gene (1.79%) and the cyt b gene (7.50%) are pronounced and suggest taxonomic distinctness (cf. Tables 1 and 3). The remaining small clade is represented only by two samples from the Northern and Western Cape provinces and by the lectotype of Pentonyx capensis Duméril & Bibron, 1835, lacking an exact geographical provenance. The sequences from the Northern and Western Cape correspond to topotypic material of Testudo galeata Schoepff, 1792 and to the holotype of Pelomedusa galeata devilliersi Hewitt, 1935 (Fritz et al. 2014). The widely distributed second clade contains, besides fresh material, also sequences of the types of Pelomedusa nigra Gray, 1863 (Fritz et al. 2014) and of a terrapin from the Western Cape (MTD T 10511, Groenfontein near Calitzdorp; Table S1). MTD T 10511 can also be considered topotypic for Testudo galeata Schoepff, 1792. Because topotypes of Testudo galeata Schoepff, 1792 are represented in both clades, the situation is nomenclaturally intricate. Moreover, the rarity of material of the small clade does not allow a morphological assessment of the situation. Therefore, we feel it is prudent to recognize for the moment only one species from South Africa, pending further study.
Unlike P. subrufa and some northern Pelomedusa species (see below), P. galeata is not parasitized by monogenean flatworms of the genus Polystomoides (Polystomatidae). These flatworms are generally found in the urinary bladder, cloaca, eye cavity, nose, mouth and pharynx of terrapins (Morrison & Du Preez 2011). They are known to be site-specific, and more than one species can be found in a single host species (Du Preez & Lim 2000). However, more than 200 Pelomedusa galeata from localities throughout its known geographical range were screened for the presence of polystomatids but none were found (Du Preez, unpubl.), indicating that this species is not susceptible to these parasites.
description: Published as part of Petzold, Alice, Vargas-Ramírez, Mario, Kehlmaier, Christian, Vamberger, Melita, Branch, William R., Preez, Louis Du, Hofmeyr, Margaretha D., Meyer, Leon, Schleicher, Alfred, Široký, Pavel & Fritz, Uwe, 2014, A revision of African helmeted terrapins (Testudines: Pelomedusidae: Pelomedusa), with descriptions of six new species, pp. 523-548 in Zootaxa 3795 (5) on pages 532-534, DOI: 10.11646/zootaxa.3795.5.2, http://zenodo.org/record/4915083