In Carl Lindroth’s (1963) classic work on the Bembidiina of Canada and Alaska, he describes some species that do not occur in Canada or Alaska. These species were always a source of some mystery to me when I was a teenager in Canada. They were set in smaller print, too, as if Lindroth were whispering their details. What were these curious foreigners? Most of these species became familiar to me later, as I collected in the States, or as I examined material in various collections. But one of those species, Bembidion ulkei Lindroth, continued to be a mystery. It was supposed to be similar to B. obscuripenne Blaisdell, which is found from the Sierra Nevada of California north into Washington state, and with which I was quite familiar.
B. ulkei was only known from the original type series of six specimens, with the locality information being nothing more specific than “Nevada”. I had never seen a specimen until last month, when I was visiting the Carnegie Museum (for an excellent carabidfest). There I was very excited to see the type series; it made the species just a little bit less mysterious. Here’s what one of the paratypes looks like:
For my current revision of the Bembidiina of America North of Mexico, one of the puzzles for me has been how to acquire B. ulkei for DNA studies. Did I need to tromp all around Nevada until I happened upon a locality? What if they were endemic to the top of just one of the many mountain ranges? How long would it take to find them?
Enter Kip Will, who had collected in Nevada last summer. In some mountains southwest of Austin, Nevada, he found a couple of specimens of this group of beetles. One of them was a male. On the off chance these were the enigmatic Bembidion ulkei, I dissected the genitalia of the male, and compared them to the figures of B. ulkei and B. obscuripenne in Lindroth’s (1963) work. Here are Lindroth’s two figures:
Look at the shape of the flagellum, and the nature of the accessory piece (including the directions these two things point), and the position of the brush sclerite. These and other details match pretty much perfectly Lindroth’s drawing of B. ulkei! Yay! Kip caught it! I didn’t have to worry about how to get that species any more!
Just for good measure, I decided to dissect one of the males of B. obscuripenne I had collected in the Sierra Nevadas last summer. I had never dissected males of this species before, but I felt confident they were B. obscuripenne, because their external characters matched the description, and because of the geographic location. Here’s the genitalia of the first one I dissected, from near Lake Tahoe:
Oh, wait. I looks just the same! B. ulkei lives in the Sierras! Well, might as well dissect a specimen from Washington, far, far away from the region of B. ulkei:
What! It’s B. ulkei as well. That makes no sense. What about Oregon (the type specimen of B. obscuripenne is from “Oregon”). Here’s one from eastern Oregon:
Lindroth only mentions dissecting two B. obscuripenne specimens: the type specimen (“Oregon”), and a specimen from Dallas, Oregon (which he designated as the type locality). Dallas, Oregon, is at the edge of the Coast Range in Oregon. The only Oregon specimens in the Oregon State Arthropod Collection of the B. obscuripenne group are from eastern Oregon, well east of the Coast Range. Perhaps B. obscuripenne only lives in the Coast Range, and is rarely caught. In a reversal of expectations, it may be that B. obscuripenne is the rare, restricted species, and B. ulkei might be the common, widespread species.
The other explanation is that Lindroth mixed up his drawings (and the accompanying text, which describes the flagellar details), and that all of the ones I dissected are truly B. obscuripenne, and that B. ulkei is still rare and mysterious. But that seems a bit less likely.
Next step: borrow males of the type series of both species, and check to see whether or not the genitalia match Lindroth’s drawings. And, if Lindroth’s drawings are correct, then its off to Dallas, Oregon, a one hour drive away, to look for more specimens.
It’s mysteries like this, and the sleuthing required to track down the story, that make taxonomy so appealing.