Prestina jenkinae

Pristina jenkinae (Stephenson, 1931) is a freshwater oligochaete worm that is an uncommon oligochaete in the Great Lakes. It is a naidid worm with dorsal and ventral bundles beginning in II, hair chaetae in the dorsal bundles, and no proboscis. In each dorsal bundle, there are 1–2 smooth hair chaetae and 1–2 bifid needles with long parallel teeth. The needles curve distally, and the teeth are frequently unequal, with the upper tooth varying from half as long to the same length as the lower tooth. Ventral bundles contain 2–9 (usually 4–6) chaetae anteriorly and 2–3 (rarely 4–5) posteriorly. The teeth of ventral chaetae are equally long, although the size of the chaetae may vary. When mature, penial chaetae appear in VII. Pristina idrensis and Pristinella jenkinae are synonyms. This genus was separated into two by Brinkhurst (1985) based on the presence (Pristina) or absence (Pristinella) of a proboscis, although Collado and Schmelz (2000) later suppressed this and recombined them based on their research.

P. jenkinae is identified mainly by dorsal bundles starting in II with smooth hairs and bifid needles with long parallel teeth and the lack of a proboscis. There are no elongate hairs. The ventral chaetae have equally long teeth. There may be penial chaetae when mature.

Widespread.

Lake Superior.

P. jenkinae most closely resembles other Pristina species that lack proboscises, especially those with simple-pointed or bifid needles with long parallel teeth. The closest species would be Pristina longidentata, which also has 1 or rarely 2 hairs and needles per dorsal bundle, but it has hispid hairs and is only found in Louisiana and Oklahoma. They have been declared synonymous in the past (Brinkhurst and Jamieson 1971), but Harman (1974) separated them. The next closest species is found in Lake Erie, which is Pristina acuminata. P. acuminata is distinguished because it has 2–5 hispid hairs and needles, and the needle teeth are long but slightly diverging. There are some Pristina species without proboscis that have short divergent bifid or pectinate needles, such as P. osborni, P. minuta, and P. sima, which have not been found in our Great Lakes samples. P. longisoma has simple-pointed needles and the hair of II elongated, but it is also not found in the Great Lakes.

Some species of Pristina have proboscises, which can sometimes be torn off. In this case, the closest species could be P. breviseta, which has 1 smooth hair and needle with long equal teeth. The ventral chaetae of II have the upper tooth longer than the lower. If unsure if there is a missing proboscis, look for more than one hair and needle, needles with unequal teeth, and ventral chaetae with equal teeth in II, which are all traits of P. jenkinae. There are several Pristina with proboscis that have long parallel but uneven teeth, such as P. plumaseta, P. synclites, and P. americana, but these are less common.

There are two other Pristina species found in our Great Lakes samples, but they both have proboscis and bifid needles with short teeth. P. longiseta has mostly hispid hairs but elongated smooth hairs in III and minutely bifid needles, with ventral chaetae with the upper tooth twice as long as the lower. P. aequiseta has hispid hairs and bifid needles, with ventral chaetae with the upper tooth up to twice as long as the lower, and there may be enlarged chaetae anteriorly. It should not be as easy to confuse these with P. jenkinae. There is also P. leidyi and P. proboscidea, which have hispid hairs and minutely bifid or simple-pointed needles.

P. jenkinae could be confused with small immature tubificids with hair, since the dorsal chaetae start in II. However, the chaetae on these naidid worms are so much smaller than immature tubificids that they often require immersion oil to differentiate.

P. jenkinae is a small freshwater oligochaete.

No, this species does not yet have a barcode reference from the Great Lakes.

Kathman, R.D., and R.O. Brinkhurst. 1998. Guide to Freshwater Oligochaetes of North America. pp. 98–99, 36, 90, 94–97, 56–61.

Hiltunen, J.K., and D.J. Klemm. 1980. A Guide to the Naididae (Annelida: Clitellata: Oligochaeta) of North America. pp. 28–29, 37.