''Sphincterochila zonata'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of air-breathing

land snail A land snail is any of the numerous species of snail that live on land, as opposed to the sea snails and freshwater snails. ''Land snail'' is the common name for terrestrial molluscs, terrestrial gastropod mollusks that have gastropod shell, shel ...

, a

terrestrial Terrestrial refers to things related to land or the planet Earth, as opposed to extraterrestrial. Terrestrial may also refer to: * Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on o ...

pulmonate Pulmonata or pulmonates is an informal group (previously an order, and before that, a subclass) of snails and slugs characterized by the ability to breathe air, by virtue of having a pallial lung instead of a gill, or gills. The group inclu ...

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusk Mollusca is a phylum of protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant species of molluscs are recognized, making it the second-largest animal phylum after Arthropoda. The ...

in the family

Sphincterochilidae Sphincterochilidae is a taxonomic family of medium-sized air-breathing land snails, terrestrial pulmonate gastropod mollusks in the superfamily Helicoidea (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). In the fossil r ...

.MolluscaBase eds. (2020). MolluscaBase. Sphincterochila zonata (Bourguignat, 1853). Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p=taxdetails&id=1259808 on 2020-12-05 It inhabits the Negev desert in

Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...

. It has been described as a synonym for a sister species, '' S. boissieri'', based on initial discoveries of the species by Bourguignat in 1853,Bourguignat J.R. (1853) “Description de quelques coquilles provenant de Syrie.” Journal de Conchyliologie. 4: 69-74. though this is not entirely clear throughout current literature. ;Subspecies: * ''Sphincterochila zonata filia'' (Mousson, 1861)shell photo 1shell drawing (figure 70–71.)
* ''

Sphincterochila zonata zonata ''Sphincterochila zonata zonata'' is a subspecies of air-breathing land snail, a terrestrial pulmonate gastropod mollusc in the family Sphincterochilidae.MolluscaBase eds. (2022). MolluscaBase. Sphincterochila zonata zonata (Bourguignat, 1853). A ...

'' (Bourguignat, 1853) (synonym: ''Helix boissieri'' Charpentier, 1847)

Anatomy and physiology

''Sphincterochila zonata'' reproduction is constituted by

hermaphroditic A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

cycles. This includes a

spermatogenic Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testicle. This process starts with the mitotic division of the stem cells located close to the basement membrane of the tubul ...

cycle which is activated through August and September and an oogenic cycle that occurs in December until January.Hodgson A. N.; Shachak M (1991). “The spermatogenic cycle and role of the hermaphrodite duct in sperm storage in two desert snails.” Invertebrate Reproduction & Development. 20: 125-136. Reproductive cycles are also linked to the weather patterns of the Negev desert region as well. Aestivation, or dormancy, in ''S. zonata'' occurs during the dry season and persists for most of the year. Characteristics of vertebrate-like hormones such as

testosterone Testosterone is the primary male sex hormone and androgen in Male, males. In humans, testosterone plays a key role in the development of Male reproductive system, male reproductive tissues such as testicles and prostate, as well as promoting se ...

estrogen Estrogen (also spelled oestrogen in British English; see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three ...

, and

progesterone Progesterone (; P4) is an endogenous steroid and progestogen sex hormone involved in the menstrual cycle, pregnancy, and embryogenesis of humans and other species. It belongs to a group of steroid hormones called the progestogens and is the ma ...

have been observed generating throughout

aestivation Aestivation ( (summer); also spelled estivation in American English) is a state of animal dormancy, similar to hibernation, although taking place in the summer rather than the winter. Aestivation is characterized by inactivity and a lowered m ...

fluxes.Alon G.; Shore L.S.; Steinberger Y (2007). “Correlation between levels of sex hormones (progesterone, testosterone, and estrogen) and ecophysiological-behavior stages in two species of desert snails (Sphincterochila zonata and Sphincterochila prophetarum) in the Northern Negev Desert.” General and Comparative Endocrinology. 151: 122-127.

Ecology

Habitat

Characterized as one of the most abundant desert snails of the central

Negev desert The Negev ( ; ) or Naqab (), is a desert and semidesert region of southern Israel. The region's largest city and administrative capital is Beersheba (pop. ), in the north. At its southern end is the Gulf of Aqaba and the resort town, resort city ...

, a region of Southern Israel, by Bourguignat in 1853. Found often in exposed areas, in opposition to other snails of this region.Arad Z.; Goldenberg S.; Heller J (1988). "Resistance to desiccation and distribution patterns in the land snail Sphincterochila." Journal of Zoology. 218: 353-364. During the rainy period of the year, occurring from November to March, ''Sphincterochila zonata'' actively feed and reproduce.Schmidt-Nielson K.; Taylor C.R.; Shkolnik A (1971). “Desert snails: problems of heat, water and food.” Journal of Experimental Biology. 55: 385-398. Furthermore, ''S. zonata'' is largely inactive during the dry season, and is only active for around ten to thirty days of the year.Goodfriend G.A.; Magaritz M (1987). "Carbon and oxygen isotope composition of shell carbonate of desert land snails." Earth and Planetary Science Letters. 86: 377-388. In dry conditions, ''S. zonata'' inhabits more sheltered areas, including under soil or bushes.Shachak M (1981). "Comparative study on the water economy of two sympatric species of desert snails (Sphincterochila zonata and S. propheterum)." Journal of Arid Environments. 4: 115-121. The diet of ''S. zonata'' consists primarily of the microflora existing within surface soils.

Significant adaptations

Of interest in this animal is its resistance to

desiccation Desiccation is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container. The ...

, which allows it to live in exposed areas in the desert.Arad Z.; Mizrahi T.; Goldenberg S.; Heller J (2010). “Natural annual cycle of heat shock protein expression in land snails: desert versus Mediterranean species of Sphincterochila.” The Journal of Experimental Biology. 213: 3487-3495. Body water in ''S. zonata'' can be maintained comparatively to other species during activity, though during inactivity body water percentage decreases over time. In a test relative to other species of ''Sphincterochila'', ''S. zonata'' was able to retain the most water and maintain water content within its soft body. Further interest exists in these snails’

hormone A hormone (from the Ancient Greek, Greek participle , "setting in motion") is a class of cell signaling, signaling molecules in multicellular organisms that are sent to distant organs or tissues by complex biological processes to regulate physio ...

levels and their yearly fluctuations in the study of aestivation. As cited from Goodfriend and Magaritz (1987), ''S. zonata'' is only active for a few days out of the year, depending on rain patterns. Aestivation is an obvious energy requirement of this organism in that it is too costly to continuously generate spermatocytes and oocytes for reproduction. Research regarding HSP production during aestivation and the regulation of arousal during this dormancy has been of interest most recently within ''S. zonata''.

Phylogeny

The genetic variability within the 15-species genus ''Sphincterochila'' is predominantly due to differences in water availability.Nevo E.; Bar-El C.; Bar Z (1983). “Genetic diversity, climatic selection and speciation of Sphincterochila land snails in Israel.” Biological Journal of the Linnean Society. 19: 339-373. ''S. zonata'' is a species

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to Israel and likely diverged from ''S. fimbriata'' (or a similar ancestor) around 1.3 million years ago.

Relation to ''Sphincterochila boissieri''

The relationship between these species is not clearly defined, and there are few citations within academic literature that acknowledge the relationship between them. There is apparent belief that the writings of Bourguignat from 1853, which describe some of the first records of ''S. zonata'', are descriptive of both ''S. zonata'' and ''S. boissieri''. Furthermore, in an article published in 1983, ''S. zonata'' is referenced with respect to studies that have been conducted concerning it, with citations of studies that describe studies on ''S. boissieri'' as well as ''S. zonata''.

References

{{Taxonbar, from=Q103871486 Sphincterochilidae Gastropods described in 1853