Fairy shrimps of Andalusia (Crustaceans: Branchiopods)

“Ghost” species locally common: an opportunity to discover this mythical group of crustaceans.

12 fairy shrimps

2 clam shrimps

1 tadpole shrimp (aggr. of cryptic species)

Mediterranean temporary pools

Extraordinary biology

Check-list Branchiopods of Andalusia

The branchiopods: arthropods, that is, invertebrates with exoskeletons, whose abdominal legs serve as gills, and are mostly restricted to continental aquatic environments. Likewise, they make up the most primitive class of the large group of crustaceans, who  are especially diverse and abundant in the sea while insects are so on the continents.

Surprising” is possibly the best word to define the branchiopods, an animal group whose natural history is often an exception and “breaks the rules”. Of course, they attract the attention because of their scarcity, but also for the curiosity of species which seem to survive against common sense.

The group is divided into four orders. A few macroscopic species are much rare but easy to notice in the field and informally coined as the Large Branchiopods. They include the tadpole shrimps, or notostaceans (literally “shell-swimmer”), represented by the genus Triops of really primitive aspect, the clam shrimps, or concostraceans (“crustaceans-clam”) with protective bivalve shell, and the most diverse and defenseless fairy shrimps, or anostaceans (“without-shell”). To complete this picture, add the broader order of water fleas, or cladocerans (“spiny branch”), which are microscopic and highly modified planktonic organisms within the class, are also bivalves and provided with a terminal spine.

Along with amphibians and various atypical ferns (Marsilea, Isoetes), the Large Branchiopods are the true specialists of temporary Mediterranean ponds and lagoons. This habitat, more abundant in arid regions, is highly threatened by changes in land use and currently considered a priority for conservation.

With 15 detected species, Andalusia represents a diversity hotspot for the group in Europe. The Andalusian Fairy Schrimp (Linderiella baetica) is the rarest and most threatened species by far, known from a single peri-urban locality and developing under specific hydrological conditions of low mineralization. Other notable species are the Iberian Clam shrimp (Cyzicus grubei), the Moorish Clam shrimp (Maghrebestheria maroccana), the aggregate of Mediterranean Triops species (Triops mauritanicus aggr.) and the Iberian Fairy Shrimp (Branchippus cortesi). We must also mention the Brine shrimps (Artemia spp) well known to the public and restricted to salt flats and salty lagoons.

Large branchiopods of Andalusia: Triops mauritanicus agg.

Spectacular Mediterranean tadpole shrimp (Triops mauritanicus agg.).

Le Triops des Maures (Triops mauritanicus)

We have been passionate about Mediterranean temporary pools and have carried out multiple inventories of large branchiopods in Andalusia.

Dynamics in temporary pools

A miniature ecosystem where to observe an ecological succession developing on a scale of days. This extraordinary dynamism and the effect of chance turn the wetlands in Andalusia into exciting environments for the nature observer.

L'anostracé Branchipus schaefferi (Branchiopoda Anostraca)

Puddle Fairy schrimp (Branchipus schaefferi): .

Grands branquiopodes (Branchiopoda)

How long can the eggs last in the substrate? What is the preference of the species depending on the depth of the water column and salinity? How many species can live in the same pond? How do these apex species colonize new bodies of water, by air and by land? Why is there especially bright coloration on the abdomen of females?

Stage 1: After prolonged rains throughout the fall and winter, the endorheic terrestrial depressions, that is, those that do not flow into streams, are saturated with water. Depending on the size of the drainage basin, ponds and even lagoons are formed on otherwise barren land, mostly characterized by sparse terrestrial vegetation, and where the seed bank of plants and branchiopod eggs goes unnoticed.

Stage 2: These habitats are little more than masses of low mineralized water, which cools overnight, and are devoid of vegetation. After a few days, the eggs hatch and the first branchiopods massively colonize the pond, feeding on algae and organic debris. Finally, the first winged insects and amphibians colonize the ponds in order to start a reproductive cycle.

Stage 3: Very variable period, depending on factors such as the volume of the water body, the physical-chemical conditions and the precipitation regime of the year. As for large branchiopods, typical deep-water and saline species develop later in season. For other species, mature females have allready layed eggs that settle to the bottom and require a drying period to hatch. In shallow ponds, the water becomes warmer, without getting so cold at night. A veritable explosion of life fills the ponds with organisms: aquatic plants have grown very vigorously, a new generation of predatory insect larvae and tadpoles have become abundant, and aquatic birds frequently visit wetlands to feed. In particular, the ardeidae (storks, egrets or herons) take advantage of abundant food of amphibians and perhaps Triops. Meanwhile, large branchiopods are increasingly scarce, being predated or not supporting maximum water temperatures.

Stage 4: The pond has passed its peak and is beginning to dry out very noticeably. The branchiopods are already very scarce, although isolated individuals achieve a considerable size. Aquatic insects and amphibians have metamorphosed in great numbers, plants have completed their life cycle. New rains could bring back the previous stage, but the end of a season is already noticeable.

Stage 5: the pond is dry, although at first humidity favors dense herbaceous vegetation, at least in non-salty soils. Quickly, the aridity gains ground and the surfaqce becomes barren again concealing its riches … until the next rains.

Libélulas de Andalucía

Large branchiopods: List of species present in Andalusia

Order

Family

Species

Common name

Identification of adults

Main distribution

Prefered habitat

Rarity

Anostraca Artemiidae Artemia franciscana San Francisco Brine shrimp Tricky Exotic Hipersaline Scarce
Artemiidae Artemia parthenogenetica diploide Diploid Brine shrimp Tricky Paleartic Hipersaline Rare
Artemiidae Artemia parthenogenetica tetraploide Tetraploid Brine shrimp Tricky Paleartic Hipersaline Rare
Artemiidae Artemia salina Brine shrimp Tricky Paleartic Hipersaline Rare
Branchipodidae Branchipus cortesi Iberian Fairy Shrimp Easy Iberian Shallow Ponds Scarce
Branchipodidae Branchipus schaefferi Puddle Fairy Schrimp Easy Paleartic Shallow Ponds Common
Branchipodidae Tanymastix stagnalis Marsh Fairy Shrimp Unmistakable Western Paleartic
Shallow Ponds Common
Chirocephalidae Branchinectella media Mediterranean Fairy Schrimp Tricky Mediterranean, Central Asia
Hipersaline Rare
Chirocephalidae Chirocephalus diaphanus Diaphanous Fairy Schrimp Easy Paleartic Shallow Ponds Most Common
Linderiellidae Linderiella baetica Andalusian Fairy Schrimp Tricky One pond in Cadix Shallow Ponds Very Rare (CR)
Streptocephalidae Streptocephalus torvicornis Tweezers Fairy Schrimp Unmistakable Paleartic Deep ponds Rare
Thamnocephalidae Phallocryptus spinosa Spiny Fairy Shrimp Easy Circummediterránea Hipersaline Rare
Notostraca Triopidae Triops mauritanicus aggr. Mediterranean tadpole shrimp agg. Unmistakable/ Dificult Ibero-maghrebian Shallow Ponds Common
Spinicaudata Cyzidae Cyzicus grubei Iberian Clam shrimp Tricky Ibero-balear Shallow Ponds Rare
Leptestheriidae Maghrebestheria maroccana Moorish Clam shrimp Tricky Ibero-maghrebian Shallow Ponds Very Rare

 

Notas

1: Publicación de referencia: 

IUCN: Riesgo de extinción, teniendo en cuenta los Libros Rojos de Andalucía (criterios regionales de la UICN), España (criterios nacionales de la UICN) y la Lista Roja UICN (análisis global). LR: Lower Risk. NT: Near Threathened. VU: Vulnerable. EN: Endangered. EX: Extinct.

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