11 November 2023

An update on the state record for Argia translata

In a previous blog post, we discussed the addition of Dusky Dancer (Argia translata) to the Michigan list. Our first "discovery" of this species for the state was two adult specimens cataloged in the University of Michigan Museum of Zoology (UMMZ) collection: a female collected on 25 June 1957 and a male collected on 7 July 1957, both by Rodger Mitchell at the University's E.S. George Reserve in Livingston County. 

We looked for these specimens at UMMZ, but couldn't locate them. Thus, we went in search of this species. On 10 September 2019, we collected a male on the Huron River at Bandemer Park, Ann Arbor, Washtenaw County. 

Male Dusky Dancer, Huron River, 10 Sep 2019.

We have also collected this species elsewhere on the Huron River in Washtenaw County, as well as the Saline River in Monroe County.

Recently, we've been working much more in the UMMZ collection. We decided to try looking for the 1957 Livingston County vouchers again. An additional motivating factor was that we have also been working with a lot of data from the E.S. George Reserve, and there are many ponds but no creeks or rivers there. Consequently, there are only a few Argia specimens, and they are all Variable (Violet) Dancer, Argia fumipennis, a species often found away from water.

In the drawer of Argia translata specimens, we found a triangle for a Variable Dancer whose data and catalog number matched one of our missing Dusky Dancer specimens.

The data sheet for the missing male "Argia translata" along with the paper triangle and matching catalog number. The triangle correctly labels it as Argia fumipennis violacea.

The damselfly in the triangle was indeed a male Variable Dancer. Although it was fragile and lacked color, you can see in the photo below that the abdomen was largely pale where it is largely dark in Dusky Dancer, and the pattern on the final segments also does not match.

The correctly identified, incorrectly cataloged specimen.

Last abdominal segments of a male Argia translata.

We did not locate the other missing voucher in the drawer of Argia translata specimens; once we found this one we only skimmed through the rest. We suspect that someone may have been entering data for Argia translata and, because this correctly labeled triangle was in the wrong drawer, just entered it as A. translata. This would be an unusual species for this location, and we are pretty confident the other missing item is not A. translata.

Therefore, the male we collected in 2019 is the first state record for this species.

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