lukas_scharer's Identifications

Wild guess on the subphylum, but it looked Metazoan to me, and I can’t think what it would be other than a flatworm. Hid under some debris most of the time so I wasn’t able to get any full body shots.

Animals were found in Lake Lagunita, a temporary body of water which fills each Winter from spillover from the nearby San Francisquito creek.

Animals were collected by collecting samples of stonewort (likely Nitella sp.), shaking the sample in a jar, and decanting through a 100 micron cell strainer.

Animals were often found with green and yellow in their guts, and feeding experiments in the lab determined that they were primarily feeding on algal cells from Nitella which had broken open. Animals also will consume ciliates and crushed brine shrimp.

As of 4/29/24, efforts to maintain the animals in the lab have been difficult, as animals begin to show strange bulges of tissue and have difficulties laying eggs in dishes (eventually they stop eating and lyse); however, providing samples of algae help promote egg laying as it provides a plausibly safe location to deposit eggs. Will update if a line can be maintained.

Update (5/2/24): Eggs from a previous batch of animals have begun hatching, and I've have had better success raising juveniles in 60mm dishes with the diatom Nitzschia curvilineata (as per Lukas' suggestion). They appear to consume the diatom, but since it's a marine diatom, I'm not sure how long they will stay edible in fresh water. Adults are being maintained in a much larger volume of water (150 mL) and provided with shredded kimwipes for egg deposition (so far the kimwipes have accumulated about 6-8 eggs overnight). I've been maintaining them all in a half/half mixture of filtered lake water and Crystal Geyser spring water supplemented with Gentamicin and Ciprofloxacin antibiotics.