Testudo (genus)

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Testudo
Temporal range: Miocene–Present
Testudo x4.jpg
Four tortoises of the genus Testudo.
Clockwise from left:
Testudo graeca ibera
Testudo hermanni boettgeri
Testudo hermanni hermanni
Testudo marginata sarda .
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Superfamily: Testudinoidea
Family: Testudinidae
Genus: Testudo
Linnaeus, 1758
Type species
Testudo graeca
Synonyms
  • FurculachelysHighfield, 1990 [1]
  • ChersusGmira, 1993
and see text.

Testudo, the Mediterranean tortoises, are a genus of tortoises found in North Africa, Western Asia, and Europe. Several species are under threat in the wild, mainly from habitat destruction.

Contents

Background

They are small tortoises, ranging in length from 7.0 to 35 cm and in weight from 0.7 to 7.0 kg.

Systematics

Distribution map of the tortoise species of the genus Testudo; overlaps and subspecies are shown Testudo tortoises - distribution map.png
Distribution map of the tortoise species of the genus Testudo; overlaps and subspecies are shown

The systematics and taxonomy of Testudo is notoriously problematic. Highfield and Martin commented:

Synonymies on Testudo are notoriously difficult to compile with any degree of accuracy. The status of species referred has undergone a great many changes, each change introducing an additional level of complexity and making bibliographic research on the taxa extremely difficult. Most early and not a few later checklists contain a very high proportion of entirely spurious entries, and a considerable number of described species are now considered invalid – either because they are homonyms, non-binomial or for some other reason. [2]

Since then, DNA sequence data have increasingly been used in systematics, but in Testudines (turtles and tortoises), its usefulness is limited: In some of these, at least mtDNA is known to evolve more slowly in these than in most other animals. [3] Paleobiogeographical considerations suggest the rate of evolution of the mitochondrial 12S rRNA gene is 1.0-1.6% per million years for the last dozen million years or so in the present genus [4] and ntDNA evolution rate has been shown to vary strongly even between different population of T. hermanni; [5] this restricts sequence choice for molecular systematics and makes the use of molecular clocks questionable.

The following extant species in the following subgenera are placed here:


The first two are more distinct and ancient lineages than the closely related latter three species. Arguably, T. horsfieldii belongs in a new genus (Agrionemys) on the basis of the shape of its carapace and plastron, [6] and its distinctness is supported by DNA sequence analysis. [7] Likewise, a separate genus Eurotestudo has recently been proposed for T. hermanni; these three lineages were distinct by the Late Miocene as evidenced by the fossil record. [8] Whether these splits will eventually be accepted remains to be seen. The genus Chersus has been proposed to unite the Egyptian and marginated tortoises which have certain DNA sequence similarities, [4] but their ranges are (and apparently always were) separated by their closest relative T. graeca and the open sea and thus, chance convergent haplotype sorting would better explain the biogeographical discrepancy.

Conversely, the Greek tortoise is widespread and highly diverse. In this and other species, a high number of subspecies has been described, but not all generally accepted, and several (such as the "Negev tortoise" and the "dwarf marginated tortoise") are now considered to be local morphs. Some, such as the Tunisian tortoise, have even been separated as a separate genus Furculachelys, but this is not supported by more recent studies. [9]

Mating

Testudo spp. are promiscuous creatures and they follow a polyandrous mating system. [10] Mating involves a courtship ritual of mechanical, olfactory and auditory displays elicited from the male to coerce a female into accepting copulation. [11] Courtship displays are very energetically costly for males, especially because females tend to run away from courting males. [12] The male will chase her, exerting more energy and elaborate displays of ramming and biting. Females are able to judge a male's genetic quality through these displays; only healthy males are able to perform costly courting rituals, suggesting endurance rivalry. [11] These are considered honest signals that are then used to influence pre- and post-copulatory choice, as females are the choosy sex. [10]

Female mate choice offers no direct benefits (such as access to food or territory or parental care). [13] There are, however, indirect benefits of mating with multiple males. Engaging in a polyandrous mating system offers a female guaranteed fertilization, higher offspring diversity and sperm competition to ensure that eggs are fertilized by a high quality male. This is in respect to the "good genes" hypothesis that females receive indirect benefits through her offspring by mating with a quality male, "a male's contribution to a female's fitness is restricted to [his] genes" (Cutuli, G. et al., 2014).

Mating order has no influence on paternity of a clutch so a female's inclination to mate with multiple males and her ability to store sperm allows for sperm competition and suggests cryptic female choice. [14] However, some species do show size-assortative, T. marginata, for example, where large males breed with large females and small males breed with small females. [11] Other species form hierarchies; during male-to-male competition the more aggressive male is considered alpha. [10] Alpha males are more aggressive with their courting as well and have higher mounting success rate than beta males.

A female's reproductive tract contains sperm storage tubules and she is capable of storing sperm for up to four years. [15] This sperm remains viable and when she goes a breeding season without encountering a male she is able to fertilize her eggs with the stored sperm. Storing sperm can also result in multiple paternity clutches; It is quite common among Testudo spp. females to lay a clutch that has been sired by multiple males. And females can lay one to four clutches a breeding season. Sexual dimorphism, promiscuity, long term sperm storage and elaborate courting rituals are factors that effect mate preference, sperm competition and cryptic female choice in genus Testudo. [10]

Related Research Articles

<span class="mw-page-title-main">Tortoise</span> Family of turtles

Tortoises are reptiles of the family Testudinidae of the order Testudines. Like other turtles, tortoises have a shell to protect from predation and other threats. The shell in tortoises is generally hard, and like other members of the suborder Cryptodira, they retract their necks and heads directly backward into the shell to protect them.

<span class="mw-page-title-main">Marginated tortoise</span> Species of tortoise

The marginated tortoise is a species of tortoise in the family Testudinidae. The species is endemic to Greece, Italy, and the Balkans in Southern Europe. It is the largest European tortoise. The marginated tortoise is herbivorous, and brumates for the winter.

<span class="mw-page-title-main">Greek tortoise</span> Species of tortoise

The Greek tortoise, also known commonly as the spur-thighed tortoise, is a species of tortoise in the family Testudinidae. Testudo graeca is one of five species of Mediterranean tortoises. The other four species are Hermann's tortoise, the Egyptian tortoise, the marginated tortoise, and the Russian tortoise. The Greek tortoise is a very long-lived animal, achieving a lifespan upwards of 125 years, with some unverified reports up to 200 years.

<span class="mw-page-title-main">Hermann's tortoise</span> Species of tortoise

Hermann's tortoise is a species of tortoise native to Europe.

<span class="mw-page-title-main">Russian tortoise</span> Species of tortoise

The Russian tortoise, also commonly known as the Afghan tortoise, the Central Asian tortoise, Horsfield's tortoise, four-clawed tortoise, Soviet Tortoise, and the (Russian) steppe tortoise, as well as the "Four-Toed Tortoise" is a threatened species of tortoise in the family Testudinidae. The species is endemic to Central Asia from the Caspian Sea south through Iran, Pakistan and Afghanistan, and east across Kazakhstan to Xinjiang, China. Human activities in its native habitat contribute to its threatened status.

<span class="mw-page-title-main">Asian forest tortoise</span> Species of tortoise

The Asian forest tortoise, also known commonly as the Mountain tortoise or Burmese Brown Mountain tortoise, is a species of tortoise in the family Testudinidae. The species is endemic to Southeast Asia. It is believed to be among the most primitive of living tortoises, based on molecular and morphological studies.

<i>Gopherus</i> Genus of tortoises

Gopherus is a genus of fossorial tortoises commonly referred to as gopher tortoises. The gopher tortoise is grouped with land tortoises that originated 60 million years ago, in North America. A genetic study has shown that their closest relatives are in the Asian genus Manouria. The gopher tortoises live in the southern United States from California's Mojave Desert across to Florida, and in parts of northern Mexico. Gopher tortoises are so named because of some species' habit of digging large, deep burrows. Most notably, Gopherus polyphemus digs burrows which can be up to 40 feet (12 m) in length and 10 feet (3.0 m) in depth. These burrows are used by a variety of other species, including mammals, other reptiles, amphibians, and birds. Gopher tortoises are 20–50 cm (7.9–19.7 in) in length, depending on the species. All six species are found in xeric habitats. Numerous extinct species are known, the oldest dating to the Priabonian stage of the Late Eocene of the United States.

<i>Geochelone</i> Genus of tortoises

Geochelone is a genus of tortoises.

<i>Aldabrachelys</i> Genus of tortoises

Aldabrachelys is genus of giant tortoises, including the Aldabra giant tortoise native to the Seychelles, as well as two extinct species, Aldabrachelys abrupta and Aldabrachelys grandidieri known from Madagascar.

<span class="mw-page-title-main">Tunisian tortoise</span> Subspecies of tortoise

The Tunisian tortoise or Nabeul tortoise is a subspecies of Greek tortoises. It was originally described as a new species in 1990, and even placed in a distinct genus. The spur-thighed or "Greek" tortoises are usually collectively referred to as Testudo graeca, but this covers a wide variety of subspecies that have very different ecological and morphological characteristics and appear to comprise at least three phylogenetic lineages. As its name implies, it is found in Tunisia and nearby Algeria.

<span class="mw-page-title-main">Kleinmann's tortoise</span> Species of tortoise

Kleinmann's tortoise, also called commonly the Egyptian tortoise, Leith's tortoise, and the Negev tortoise, is a critically endangered species of cryptodire turtle in the family Testudinidae. The species is native to Egypt, Libya, and Israel/ Palestine. The species was once more widespread, but its numbers are now dwindling. The species is nearly extinct in Egypt, and complete extinction in the wild is a looming threat unless more actions are taken to protect this species.

<span class="mw-page-title-main">Yellow-footed tortoise</span> Species of reptile

The yellow-footed tortoise, also known as the Brazilian giant tortoise, is a species of tortoise in the family Testudinidae and is closely related to the red-footed tortoise. It is found in the Amazon Basin of South America. The species name has often been misspelled as denticulata, an error introduced in the 1980s when Chelonoidis was elevated to genus and mistakenly treated as feminine, an error recognized and fixed in 2017.

<span class="mw-page-title-main">Spur (zoology)</span> Anatomical term for an outgrowth of bone covered in a sheath of horn

A spur is an outgrowth of bone covered in a sheath of horn found in various anatomical locations in some animals. Unlike claws or nails, which grow from the tip of the toes, spurs form from other parts of the foot, usually in connection with joints where the toes meet the foot or the foot meets the long bones. Spurs are most commonly found on the hindfeet, though some birds possess spurs at the leading edge of the wings.

<span class="mw-page-title-main">Polyandry in animals</span> Class of mating system in non-human species

In behavioral ecology, polyandry is a class of mating system where one female mates with several males in a breeding season. Polyandry is often compared to the polygyny system based on the cost and benefits incurred by members of each sex. Polygyny is where one male mates with several females in a breeding season . A common example of polyandrous mating can be found in the field cricket of the invertebrate order Orthoptera. Polyandrous behavior is also prominent in many other insect species, including the red flour beetle and the species of spider Stegodyphus lineatus. Polyandry also occurs in some primates such as marmosets, mammal groups, the marsupial genus' Antechinus and bandicoots, around 1% of all bird species, such as jacanas and dunnocks, insects such as honeybees, and fish such as pipefish.

<i>Titanochelon</i> Genus of tortoises

Titanochelon is an extinct genus of giant tortoises known from the Early Miocene to the beginning of the Pleistocene in Europe, extending from the Iberian Peninsula to Anatolia. Some members of the genus were larger than extant giant tortoises, with a shell length of up to 2 m.

<i>Solitudo</i> Extinct genus of turtle

Solitudo is an extinct genus of tortoise that was found during the Pliocene and Pleistocene on the Mediterranean islands of Menorca, Malta and Sicily. The genus includes three described species, Solitudo robusta, Solitudo gymnesica and Solitudo sicula as well as a likely fourth, undescribed species from Monte Pellegrino in Sicily. Solitudo sicula, the youngest of the species, died out approximately 12.5 thousand years BP. The largest species, Solitudo gymnesica, has been estimated to have reached a carapace length of 1.1–1.3 m (3.6–4.3 ft).

References

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  3. Avise, J. C.; Bowen, B. W.; Lamb, T.; Meylan, A. B.; Bermingham, E. (1992). "Mitochondrial DNA evolution at a turtle's pace: Evidence for low genetic variability and reduced microevolutionary rate in the Testudines". Molecular Biology and Evolution. 9 (3): 457–473. doi: 10.1093/oxfordjournals.molbev.a040735 . PMID   1584014.
  4. 1 2 Van Der Kuyl, Antoinette C.; Ph. Ballasina, Donato L.; Dekker, John T.; Maas, Jolanda; Willemsen, Ronald E.; Goudsmit, Jaap (2002). "Phylogenetic Relationships among the Species of the Genus Testudo (Testudines: Testudinidae) Inferred from Mitochondrial 12S rRNA Gene Sequences". Molecular Phylogenetics and Evolution. 22 (2): 174–183. doi:10.1006/mpev.2001.1052. PMID   11820839.
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  6. Khozatsky, L.I. & Mlynarski, M. (1966): Agrionemys - nouveau genre de tortues terrestres (Testudinidae) ["Agrionemys - a new genus of tortoises"]. [Article in French[ verification needed ]] Bulletin de l'Académie Polonaise des Sciences II - Série des Sciences Biologiques2: 123-125.
  7. Fritz, Uwe; Široký, Pavel; Kami, Hajigholi; Wink, Michael (2005). "Environmentally caused dwarfism or a valid species—Is Testudo weissingeri Bour, 1996 a distinct evolutionary lineage? New evidence from mitochondrial and nuclear genomic markers". Molecular Phylogenetics and Evolution. 37 (2): 389–401. doi:10.1016/j.ympev.2005.03.007. PMID   16223676.
  8. De Lapparent De Broin, France; Bour, Roger; Parham, James F.; Perälä, Jarmo (2006). "Eurotestudo, a new genus for the species Testudo hermanni Gmelin, 1789 (Chelonii, Testudinidae)". Comptes Rendus Palevol. 5 (6): 803–811. Bibcode:2006CRPal...5..803D. doi:10.1016/j.crpv.2006.03.002.
  9. Van Der Kuyl, Antoinette C.; Ballasina, Donato LP; Zorgdrager, Fokla (2005). "Mitochondrial haplotype diversity in the tortoise species Testudo graeca from North Africa and the Middle East". BMC Evolutionary Biology. 5: 29. doi: 10.1186/1471-2148-5-29 . PMC   1097724 . PMID   15836787.
  10. 1 2 3 4 Cutuli, Giulia; Cannicci, Stefano; Vannini, Marco; Fratini, Sara (2014). "Influence of male courtship intensity and male-male competition on paternity distribution in Hermann's tortoise, Testudo hermanni hermanni (Chelonia: Testudinidae)". Biological Journal of the Linnean Society. 111 (3): 656–667. doi: 10.1111/bij.12243 . hdl: 2158/844715 .
  11. 1 2 3 Sacchi, Roberto; Galeotti, Paolo; Fasola, Mauro; Ballasina, Donato (2003). "Vocalizations and courtship intensity correlate with mounting success in marginated tortoises Testudo marginata". Behavioral Ecology and Sociobiology. 55: 95–102. doi:10.1007/s00265-003-0685-1. S2CID   9968063.
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  15. Roques, S.; Díaz-Paniagua, C.; Andreu, A. C. (2004). "Microsatellite markers reveal multiple paternity and sperm storage in the Mediterranean spur-thighed tortoise, Testudo graeca". Canadian Journal of Zoology. 82: 153–159. doi:10.1139/Z03-228.