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The Bernier Cave on San Salvador Island (Bahamas) was discovered in 1964 by a team led by Dr. Maurice Bernier. The cave is known for its archaeological finds, particularly bones from extinct mammals.In 2015, a research team collected three specimens of the rare hydromedusa Vallentinia gabriellae Vannucci Mendes, 1848 in the cave.
The entrance to the cave, which is located directly above or near the water, receives a lot of detritus and daylight, causing the diatom Campylodiscus neofastuosus to form there.The detritus also contained nematodes, ostracods, copepods, ciliates, dinoflagellates, foraminifera, cyanobacteria, other bacteria, and a sticky biofilm containing extracellular polymeric substances (EPS). Water movement in the cave is very slow.Occasionally, birds fly through the entrance chamber, and female buffy flower bats Erophylla sezekorni (Gundlach, 1861) with young sometimes rest in dark areas of the cave, whose excrement contributes to further nutrient enrichment.In 2025, in this cave, which has a salinity of 35 ppt and a water temperature of 23–25 °Celsius, sea stars were discovered in knee-deep water in dark areas of the cave.
These sea stars are highly paedomorphic and are the only known cave-dwelling (stygobitic) ophiuroids.These starfish feed exclusively on detritus. Finding these exceptionally small starfish, which have a disc diameter of 3–4 mm and short arms of up to 10 mm in adulthood and blend in well with the detritus due to their lack of pigmentation, was extremely difficult.Newborn starfish have a completely white body disc with a diameter of ~0.8 mm and ~30 rows of disc scales. After a few weeks, the small starfish become more pentagonal.
Only one arm segment was located within the disc; all three babies had only two segments per arm outside the disc, with the exception of baby no. 1, which had the beginning of a third segment on one arm. Good ventral views of the babies were not available in the first few months. All began to eat detritus within a few days of birth, and detritus remained their only food source throughout their lifespan, which was up to 14.5 months.
The babies reacted negatively to the dim light under which they were observed (otherwise they were in complete darkness), moving away from the light and sometimes hiding under or behind detritus to protect themselves from direct light.The feeding behavior of the small starfish was observed in the laboratory:
Before feeding, the adult starfish usually had light yellow discs that were so transparent that internal structures such as the gonads could be seen. When a few drops of fresh detritus were added to their culture vessels, they often began to ingest the detritus within minutes and their discs turned brown.The starfish pulled the detritus into their mouths with their tube feet; there appeared to be no chewing or selection or filtering of the various light and dark components as the detritus flowed into their mouths (microphagous detritus uptake).
The movement of the baby starfish is described as podial walking. In adult starfish, both testes and ovaries could be detected (hermaphroditism).Brood care in Amphicutis stygobita appears to take place in the ovaries, as no bursa could be identified in this study or in the preparations carried out for the original description. The starfish usually had 10 eggs and would not normally have had enough space in a bursa.Interesting facts about regeneration rates: two adult animals were observed to regenerate their arm tips within 24 weeks at a rate of up to 1 mm, which is one of the slowest regeneration rates reported for a starfish species.
Overall, the babies also developed very slowly in terms of size. Since Amphicutis stygobita was the first known cave-dwelling brittle star, a list of possible troglomorphisms observed in this species was compiled, including:(1) no body pigmentation, (2) reduced body size, (3) elongated arm segments, (4) raised skin, possibly to improve chemoreception, (5) subdued alarm response to light, (6) reduced aggregation, (7) reduced fertility, and (8) slow metabolism (movement and regeneration).
It should be noted that Amphicutis stygobita exhibits more troglomorphisms and paedomorphisms than the three other species studied in the study, which may be due to a longer evolutionary history in cave habitats and/or the special characteristics of Bernier's Cave, in particular its low salinity and rich detritus.
Reference: Carpenter JH (2025) Amphicutis stygobita (Echinodermata, Ophiuroidea, Amphilepidida, Amphilepididae), a brooding brittle star from anchialine caves in The Bahamas: feeding, reproduction, morphology, paedomorphisms and troglomorphisms.Subterranean Biology 51: 147-196. https://doi.org/10.3897/subtbiol.51.152663This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Literature reference:
Carpenter JH (2025) Amphicutis stygobita (Echinodermata, Ophiuroidea, Amphilepidida, Amphilepididae), a brooding brittle star from anchialine caves in The Bahamas: feeding, reproduction, morphology, paedomorphisms and troglomorphisms.
Subterranean Biology 51: 147-196. https://doi.org/10.3897/subtbiol.51.152663
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
The entrance to the cave, which is located directly above or near the water, receives a lot of detritus and daylight, causing the diatom Campylodiscus neofastuosus to form there.The detritus also contained nematodes, ostracods, copepods, ciliates, dinoflagellates, foraminifera, cyanobacteria, other bacteria, and a sticky biofilm containing extracellular polymeric substances (EPS). Water movement in the cave is very slow.Occasionally, birds fly through the entrance chamber, and female buffy flower bats Erophylla sezekorni (Gundlach, 1861) with young sometimes rest in dark areas of the cave, whose excrement contributes to further nutrient enrichment.In 2025, in this cave, which has a salinity of 35 ppt and a water temperature of 23–25 °Celsius, sea stars were discovered in knee-deep water in dark areas of the cave.
These sea stars are highly paedomorphic and are the only known cave-dwelling (stygobitic) ophiuroids.These starfish feed exclusively on detritus. Finding these exceptionally small starfish, which have a disc diameter of 3–4 mm and short arms of up to 10 mm in adulthood and blend in well with the detritus due to their lack of pigmentation, was extremely difficult.Newborn starfish have a completely white body disc with a diameter of ~0.8 mm and ~30 rows of disc scales. After a few weeks, the small starfish become more pentagonal.
Only one arm segment was located within the disc; all three babies had only two segments per arm outside the disc, with the exception of baby no. 1, which had the beginning of a third segment on one arm. Good ventral views of the babies were not available in the first few months. All began to eat detritus within a few days of birth, and detritus remained their only food source throughout their lifespan, which was up to 14.5 months.
The babies reacted negatively to the dim light under which they were observed (otherwise they were in complete darkness), moving away from the light and sometimes hiding under or behind detritus to protect themselves from direct light.The feeding behavior of the small starfish was observed in the laboratory:
Before feeding, the adult starfish usually had light yellow discs that were so transparent that internal structures such as the gonads could be seen. When a few drops of fresh detritus were added to their culture vessels, they often began to ingest the detritus within minutes and their discs turned brown.The starfish pulled the detritus into their mouths with their tube feet; there appeared to be no chewing or selection or filtering of the various light and dark components as the detritus flowed into their mouths (microphagous detritus uptake).
The movement of the baby starfish is described as podial walking. In adult starfish, both testes and ovaries could be detected (hermaphroditism).Brood care in Amphicutis stygobita appears to take place in the ovaries, as no bursa could be identified in this study or in the preparations carried out for the original description. The starfish usually had 10 eggs and would not normally have had enough space in a bursa.Interesting facts about regeneration rates: two adult animals were observed to regenerate their arm tips within 24 weeks at a rate of up to 1 mm, which is one of the slowest regeneration rates reported for a starfish species.
Overall, the babies also developed very slowly in terms of size. Since Amphicutis stygobita was the first known cave-dwelling brittle star, a list of possible troglomorphisms observed in this species was compiled, including:(1) no body pigmentation, (2) reduced body size, (3) elongated arm segments, (4) raised skin, possibly to improve chemoreception, (5) subdued alarm response to light, (6) reduced aggregation, (7) reduced fertility, and (8) slow metabolism (movement and regeneration).
It should be noted that Amphicutis stygobita exhibits more troglomorphisms and paedomorphisms than the three other species studied in the study, which may be due to a longer evolutionary history in cave habitats and/or the special characteristics of Bernier's Cave, in particular its low salinity and rich detritus.
Reference: Carpenter JH (2025) Amphicutis stygobita (Echinodermata, Ophiuroidea, Amphilepidida, Amphilepididae), a brooding brittle star from anchialine caves in The Bahamas: feeding, reproduction, morphology, paedomorphisms and troglomorphisms.Subterranean Biology 51: 147-196. https://doi.org/10.3897/subtbiol.51.152663This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Literature reference:
Carpenter JH (2025) Amphicutis stygobita (Echinodermata, Ophiuroidea, Amphilepidida, Amphilepididae), a brooding brittle star from anchialine caves in The Bahamas: feeding, reproduction, morphology, paedomorphisms and troglomorphisms.
Subterranean Biology 51: 147-196. https://doi.org/10.3897/subtbiol.51.152663
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
