24,000th iNaturalist Observation: Atalantycha bilineata (Two-lined Leatherwing)

On 9 April 2026 I made my 24,000th iNaturalist observation (at left). The observation was of Atalantycha bilineata (Two-lined Leatherwing) spotted on a walk through Hillside Park (in Arlington, VA). I ended up observing three individuals (see all my observations of Atalantycha bilineata here).

Atalantycha bilineata was originally described by American entomologist Thomas Say in 1823 under the binomial name Cantharis bilineata in the Journal of the Academy of Natural Sciences of Philadelphia (volume 3, page 182):

6. C. bilineatus. Rufous; elytra black; thorax with two black lines. Inhabits the United States.

The eagle-eyed will note that Say indicates the species as C. bilineatus, not C. bilineata. Why you ask, well, the discrepancy arises from the gender of the species name, which must agree with the genus name Cantharis (feminine). While it was sometimes historically listed with the masculine suffix -us, the correct scientific name based on ICZN rules is Cantharis bilineata.

At right: Say, T. (1823). Cantharis bilineata. In Journal of the Academy of Natural Sciences of Philadelphia (Vol. 3, p. 182). Zenodo. https://doi.org/10.5281/zenodo.19498272

The species had kept the Cantharis bilineata name until 2005 when Sergey Kazantsev's review of the genus established the new Nearctic genus Atalantycha to accommodate certain species, including A. bilineata as a new combination.

iNaturalist Observations: In and Around Copenhagen (22-31 March 2026)

Nesting Mute Swan

I attended the 2026 GBIF Midterm meetings in Copenhagen in March 2026. I added on a few days of holiday to visit some of my favorites in the city.

The weather wasn't really good for a lot of observations and I didn't get out of the city, so many of my observations were of birds (especially around the Lakes). 

Total: 23-31 March 2026 (as of 1 April 2026)

• Observations: 89

• Species: 38

Notables

• Eurasian wigeon (Mareca penelope)

• Great Tit (Parus major)

• Deer (partial jaw)

Here are all my observations from various trips to Denmark: Denmark: My Observations

Jaw of a species of Dear

First Spotted Lanternfly (Lycorma delicatula) observation of the year

 

Last year, I made my first Lycorma delicatula observation on 13 April 2025. This year, it was 10 days earlier (3 April 2025) in nearly the same spot. With the large number of (visible) egg masses in my neighborhood, I fear it will be another booming year. 

In 2025, I made 1,519 observations in Arlington, Virginia.

My iNaturalist Year in Review: 7,304 observations | 1,164 species | 114 identifications

A very busy year with iNaturalist. Of course many of those observations (1,575!) were Spotted Lanternflies (Lycorma delicatula). My species count was also helped by visiting New Zealand, Colombia, and San Francisco.

You can see the full 2025 report here.

iNaturalist Observations: In and Around London (23 December 2025 - 2 January 2026)

I was back in the United Kingdom again in later December, spent most of the time in Richmond Upon Thames, but had a few side visits around London and also a day trip to Lewes. 

At right is a Pellitory-of-the-Wall (Parietaria judaica): 

Parietaria judaica, spreading pellitory, is a species of herbaceous perennial flowering plant in the family Urticaceae. It is native to the eastern Mediterranean and Middle East, and is widely established worldwide as an urban weed. Its pollen is a significant cause of asthma and other allergies in warmer countries, but it is also valued as a contributor to biodiversity in polluted cities and it has been used as a medicinal herb. -- iNaturalist

My Observations

Total: 23 December 2025 - 2 January 2026 (as of 4 January 2026)

• Observations: 67

• Species: 29

Notables

• 46 of the 67 observations were birds!

iNaturalist Observations: In and Around London (30 November - 8 December 2025)

I spent some time in and around London in early December 2025 to attend the Fantastic Futures 2025: AI Everywhere, All at Once at the British Library. I spend most of my time in London proper, but did have a few side-trips to Richmond and Greenwich/New Cross.

At right is a Missing-Sector Orbweb Spider (Genus Zygiella):

Zygiella is a genus of orb-weaver spiders first described by F. O. Pickard-Cambridge in 1902. In 2015, Parazygiella was determined to be a taxonomic synonym of Zygiella, and its species were moved to Zygiella. 

Identification
Zygiella species are distinguished by the structure of the web, which has a missing sector containing a signaling thread leading to a retreat. Zygiella x-notata, a species in the Zygiella genus, is well-researched for its missing-sector web construction behaviors. -- iNaturalist

My Observation

Total: 30 November - 8 December 2025 (as of 9 December 2025)

• Observations: 34

• Species: 17

Notables

• Noble False Widow (Steatoda nobilis)