Adventures in Taxonomy

Apparently today is “Taxonomist Appreciation Day,” so I suppose it’s an appropriate time to write a little something about my latest paper, which I discovered had been published right after I clicked “publish” on my previous blog post. I never intended to become involved in taxonomy at all, but as a naturalist, it gets really hard to make sense of the world when so many of the species I’m studying don’t have names. If I meet a species that no one has gone to the trouble to describe and name, how can I tell how it relates to anything anyone has found before? Once there are names to which to attach observations, I can start to understand patterns in the habits and host plants (or host insects) of different species, and how these differ from species to species. Somebody needs to do the hard work of deciding what the limits are between similar species, and illustrating (in words and pictures) what the differences are. As summarized here, I’ve now had the pleasure of collaborating with various taxonomists to give names to over 60 species of insects whose natural history I’ve written about. This latest paper* doesn’t describe any new species, but it makes several taxonomic changes involving the names of leaf-mining moths in the family Gracillariidae.

It all started in March of 2017, when Julia and I stopped in Arizona on our way home from checking out the “super bloom” in southern California. Although nothing had leafed out yet in the canyons we visited, we found a number of different active mines in the leaves of evergreen trees and shrubs, and we had good success in rearing adults from most of them. These included a Cameraria species on Arizona madrone (Ericaceae: Arbutus arizonica)…

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…and another Cameraria on silverleaf oak (Fagaceae: Quercus hypoleucoides):

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When we got home and I started trying to identify all the leaf mines we had found using the keys I’d written, I found that most of them were new to science. These two species were among the few that had names (or at least, that had names that could be linked to leaf mines that had been described in the literature). To my surprise, they were Phyllonorycter arizonella and P. cretaceella. But they both were clearly Cameraria, based both on the leaf mines (flat, on the upper surface, with a longitudinal crease along one margin when complete) and the adult wing pattern (the black edging was on the outer edge of the white markings). I checked the original descriptions; both were species that Annette Braun had described in 1925 from specimens she reared in Arizona, and no one had published anything about them since. She described both species in the genus Lithocolletis, which is now considered a junior synonym of Phyllonorycter but in 1925 also included all the species that are now placed in Cameraria. The genus Cameraria was actually described in 1902—it was named for the Kentucky lepidopterist V. T. Chambers (“camera” being Latin for “chamber”)—but it was decades before the name was adopted for North American species, and most species of “Lithocolletis” didn’t receive their currently recognized names until Don Davis transferred them to Cameraria and Phyllonorycter in the 1983 Check List of the Lepidoptera of America North of Mexico.

Phyllonorycter species mostly make leaf mines on the undersides of leaves, and rather than remaining flat they usually become strongly wrinkled and “tentiform.” I decided to review the leaf mine descriptions of all the other North American Cameraria and Phyllonorycter species to see if any others were on the “wrong” side of the leaf. I found a number of other examples of Phyllonorycter species that sometimes or always make upper-surface mines, but based on features of the larvae and adults (larvae becoming round in cross section in later instars, rather than remaining flat; adult forewings with black edging on the inner margins of the white markings, rather on the outer margins), they appeared to be proper Phyllonorycter species. However, among the Cameraria species there were two that formed underside tentiform mines, and a little investigation suggested that they actually belonged in Phyllonorycter. One was C. leucothorax, which mines leaves of tanoak (Notholithocarpus densiflorus) and canyon live oak (Quercus chrysolepis) in Oregon and California. I’ve never reared it, but this is probably its mine:

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The other was Cameraria affinis, an eastern species that mines leaves of honeysuckles and snowberries (Caprifoliaceae: Lonicera and Symphoricarpos).

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I wrote to Don Davis about this, and he agreed that all four species were misplaced and should be transferred as I suggested, changing their names to Cameraria arizonella, C. cretaceella, Phyllonorycter affinis, and P. leucothorax. I thought I would just write a short note to set things right, but he felt that something more detailed was warranted, including illustrations of the male and female genitalia of each species, which he offered to provide. He had never seen specimens of C. arizonella (the six that Julia and I reared may be the only ones beyond Annette Braun’s original five, which are in Philadelphia now), so I sent him a male and female of that species, along with whichever sex he was missing for P. affinis. He had reared his own series of C. cretaceella in New Mexico in 1989, and fortunately he already had what he needed for P. leucothorax as well.

When I submitted the manuscript to Zootaxa, I suggested Terry Harrison as a possible reviewer. This turned out to be a very good idea, because when Terry was looking over the manuscript and illustrations, he was struck by the resemblance of Phyllonorycter affinis—in both wing pattern and genitalia—to the species he calls P. mariaeella. As it happens, last October when I visited Harvard University with Julia to give a slideshow about leafminers to the Cambridge Entomological Club, we showed up early and spent a few hours photographing V. T. Chambers’ type specimens that are housed at the Museum of Comparative Zoology. Unfortunately there is no type specimen for P. mariaeella—whatever existed may have been devoured by dermestid beetles, as happened to many of Chambers’ specimens while he was still alivebut filed under that name there are three specimens reared by Mary Murtfeldt in Kirkwood, Missouri. She was the namesake of P. mariaeella, and the species was described from specimens she reared at that same location, so these were as close to type specimens of P. mariaeella as could be hoped for.

Here’s one she reared from snowberry:

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And one of two she reared from honeysuckle:

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Annette Braun, in her 1908 revision of the genus “Lithocolletis“, had distinguished affinis and mariaeella based on the forewing fasciae (white markings) being “nearly straight”
in the former and “distinctly bent outward near the middle” in the latter. Terry dissected a series of Illinois specimens showing a full range of variation in these markings and found that they all had matching genitalia. David Lees at the Natural History Museum in London was kind enough to send photos of one of the affinis type specimens and its genitalia, and these too matched Terry’s specimens from Illinois as well as Mary Murtfeldt’s specimens from Missouri, and these in turn matched Chambers’ description of mariaeella. Since Chambers described mariaeella in 1875 and affinis was described in 1876 (by Frey & Boll, a couple of German lepidopterists studying material from Texas), mariaeella has priority, and Don and I have designated affinis as a synonym. One less leaf-mining moth to worry about!

The other reviewer I suggested for this manuscript, Steven Whitebread, noticed another possible synonymy when reviewing our illustrations. This is one of the type specimens of Phyllonorycter gemmea, another Frey & Boll species, but one collected in Massachusetts rather than Texas (and that, I suppose, is why part of its type series is deposited in Cambridge, MA rather than in London):

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It was allegedly reared from black locust (Fabaceae: Robinia pseudoacacia), but Frey & Boll had some mix-ups with the leaves they had collected and they weren’t sure what type of mine it had come from. They described three different types of mines they had found on black locust, which clearly correspond with three other gracillariids: Chrysaster ostensackenella, Macrosaccus robiniella, and Parectopa robiniella. Braun (1908) incorrectly cited Frey & Boll as having said that Phyllonorycter gemmea makes an upper-surface mine, which is how this species ended up getting mentioned in this “wrong side of the leaf” paper. Chambers was convinced that this moth hadn’t come from black locust at all, and I’m inclined to agree. Steven suggested that it might be synonymous with P. diversella, a leafminer of huckleberry (Ericaceae: Gaylussacia baccata) that Annette Braun described decades later. It does seem plausible that if Frey & Boll had a bunch of mixed-up leaves, they could have mistaken a huckleberry leaf for a leaflet of black locust. But as I considered this possibility, I found two other species that Braun describedP. martiella from birch, and P. viburnella from arrowwoodthat also have a similar wing pattern, and the only way to sort this out will be to dissect the specimen in the above photo (which is the only specimen in the type series that still has an abdomen) and compare its genitalia with those of specimens reared from huckleberry, birch, and arrowwood. A bit beyond the scope of this paperone of many taxonomic issues that still need to be worked out involving species that already have names, let alone the countless ones that remain to be described.

And so, a big thanks to all taxonomistspast, present, and futurefor your ongoing work to help the rest of us make sense of the complexity of nature!

* Eiseman, Charles S. and Donald R. Davis. 2020. Wrong side of the leaf: assigning some Lithocolletinae species (Lepidoptera: Gracillariidae) to their proper genera. Zootaxa 4751(2): 201–237.

About Charley Eiseman

I am a freelance naturalist, endlessly fascinated by the interconnections of all the living and nonliving things around me. I am the lead author of Tracks & Sign of Insects and Other Invertebrates (Stackpole Books, 2010), and continue to collect photographs and information on this subject. These days I am especially drawn to galls, leaf mines, and other plant-insect interactions.
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1 Response to Adventures in Taxonomy

  1. susantcloutier says:

    Wow! Those people who devote time and energy to the sorting out of who is who are amazing. And so is life. Take care you two. You help us make sense of the world and remind us to enjoy the gift of life.

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