Spindly Leg Syndrome (SLS)
(AKA, Matchstick Disease)
(AKA, Matchstick Disease)
Preventable, not curable.
(Photo credit: Anonymous)
DESCRIPTION:
This condition becomes noticeable during the late growth stages of tadpole, usually only noticed upon morphing. The newly emerged froglet (metamorph) struggles to hold himself up with the front legs. SLS froglets have wire-thin, mishappen, or even completely missing front legs. They often splay out and cannot support their weight. Often times these froglets cannot emerge from the water and are found drowned.
CAUSE:
Graduate student Kathleen Higgins worked with endangered Andinobates geminisae tadpoles to determine links with SLS, and found that an improperly balanced phosphorus levels had direct relationship with SLS.
She tested three other theories (general deficiency of B vitamins, specific deficiency in folic acid (vitB9), and not using reconstituted RO water for tadpoles), but found them to be lacking in evidence.
A theory common in the dart frog hobby is that the parents were not properly supplemented and the lack of vitA in particular can increase SLS rates. Anecdotal evidence points to addressing the supplements usually resolves the issue. More research is needed, but addressing water quality and supplements is a good path to success.
A healthy Andinobates geminisae (CC)
IMG_0077 | Brian Gratwicke | Flickr
TREATMENT:
Unfortunately, there is no treatment or cure for SLS. Because of this, it is recommended to humanely euthanize these metamorphs. One can expect only a few days of life after they emerge from water. See Humane Euthanasia for more information.
To prevent future clutches from developing SLS, there are a number of things to try:
First, replace all supplements with fresh and proper supplements if they are: 1) older than 6months after opening, 2) have not been stored in the refrigerator or freezer, or 3) are not suitable for dart frogs. Please see Supplements for more information.
If not utilizing already, consider adding a vitamin A supplement into your dusting rotation. General recommendation is to dust feeders and offer them 2x/month. Do note that vitamin A is fat soluble, building up in the body and becoming toxic if dosed too often. Please note that while it has been used 1x/week to treat deficiencies, it should not be dosed this frequently for very long. Start with 2x/month and re-evaluate.
Second, and seemingly just as if not more important, test your water and address the issue of Ca:P ratios as needed. If using unbalanced tap or well water, switching from that to remineralized RO water might just solve the problem.
Third, if the clutches are from an established pair that have not showed SLS before, consider setting the tank through a dry cycle to reduce / stop the frogs from wanting to lay eggs. This will give them a break and enable their bodies to build up their reserves. This has been helpful for older frogs once thought to be too old to produce viable eggs.
RESOURCES / FUTHER INFO:
- AmphibiCast interview with Kathleen Higgins:
Understanding Spindly Leg Syndrome with Kathleen Higgins (Episode 90) • AmphibiCast (spotify.com)
Access to her research paper:
https://theses.lib.sfu.ca/file/thesis/5427.
COMPARISONS
Oophaga pumilio 'Salt Creek'
Healthy froglet metamorph
(Photo credit: Nikki Sigmon)
Oophaga pumilio 'Salt Creek'
Metamorph with SLS showing in front feet.
Front feet cannot support / lift the head.
(Eyes are discolored due to light/flash glare)
(Photo credit: Nikki Sigmon)
Dendorbates tinctorius 'Azureus'
Healthy metamorph with remaining tail.
Still has baby fat/soft edges, but note the thick front arms showing no SLS.
(Photo credit: Nikki Sigmon)
Dendrobates tinctorius 'Azureus'
Both front feet are affected by SLS, and froglet is unable to hold head above the ground.
(Photo credit: Anonymous)
Ranitomeya imitator 'Green'
Healthy metamorph with well proportioned and functioning front arms
(Photo credit: Nikki Sigmon)
Ranitomeya
Both front feet are affected by SLS, and froglet is unable to hold head above the ground.
(Photo credit: Anonymous)