03 de julho de 2020

Teneral cicadas

I started annotating large numbers of teneral cicadas as such. To do this for a given observation, I go to an observation and then under "Observation fields," I type "teneral." It gives you the option of selecting "Yes," "No," or "Maybe." I alway select yes, since I'm doing this only for tenerals. I then push "Add" and it's done. After the first time, "teneral" shows up in the "Observation fields" menu, so you won't have to type it.

So far the number of cicadas annotated as teneral number 1254. I have focused on the southeastern and central U.S. so far. You can see them here: https://www.inaturalist.org/observations?place_id=97394&taxon_id=50190&field:teneral=yes . Note the "&field:teneral=yes" part of the URL. This can be added to any explore or identify URL to restrict the observations to tenerals.

What is the value of such annotations? It will help us better understand how to identify them as they are more difficult to identify than fully hardened specimens. One can browse given species, to develop a feel for the appearance of their tenerals. For example, here are all the teneral Neotibicen superbus, via identify:

https://www.inaturalist.org/observations/identify?reviewed=any&quality_grade=needs_id%2Cresearch&taxon_id=469277&field%3Ateneral=yes

To look at the tenerals for a given species, simply go to identify and select the species of interest, under Filters, toggle on "Research grade" and "needs Id" and select Reviewed as "any" and push "Update search." The add "&field:teneral=yes" to the URL and hit the return key. You can then browse as many as you like.

Unfortunately the current state of affairs is that a lot of tenerals are misidentified, so keep that in mind as you browse. I like to pay particular attention to those identified by @billreynolds, @rlsanders, @easmeds and @willc-t four experts on US cicadas. Those identified only by others are very likely to be misidentified.

I encourage @willc-t and @easmeds and others to annotate any tenerals they see.

Publicado em 03 de julho de 2020, 05:36 TARDE por dan_johnson dan_johnson | 0 comentários | Deixar um comentário

13 de julho de 2019

iNaturalist: Idaho vs Texas

I did some inaturalist observing in Idaho, my home state, for a few days recently, while visiting family. Idaho has a total of only 54,802 observations for the whole state, compared to 2,059,416 for Texas. That's 37 times as many observations for Texas. When looking at the populations; however, Idaho is home to 1.7 million people compared to 28.7 in Texas, with the Texas population being 16.8 times the Idaho population. Taking this into account, Idaho has half the observations per capita as does Texas.

Publicado em 13 de julho de 2019, 05:38 TARDE por dan_johnson dan_johnson | 0 comentários | Deixar um comentário

04 de setembro de 2018

New monograph on Texas crayfish published

A monograph I authored has just been published in Zootaxa. It's titled "The subgenus Ortmannicus (Decapoda: Cambaridae) in Texas, with descriptions of new species." Included are three new species:

Procambarus albaughi
Procambarus fayettei
Procambarus parvus

If anyone wants a reprint, let me know.

Publicado em 04 de setembro de 2018, 01:50 MANHÃ por dan_johnson dan_johnson | 1 comentário | Deixar um comentário

02 de julho de 2018

Increases in crayfish observations over the last 10 years.

Over the last 10 years on iNaturalist, the number of crayfish observations each year has been between 1.5 to 2.1 times the number observed the previous year. During the last five years, the number has been very close to 2 (1.8-2.1). Here is the breakdown of number of observations and factors for each year:

2743 2.0
1402 1.8
761 2.1
367 1.9
195 1.8
106 1.7
63 1.5
41 1.6
26 1.5
17 --

There was 161 times the number of crayfish observations during the last year than there was during a year ten years ago. I think this trend follows the same trend for iNaturalist as a whole. How long will this amazing trend continue?

Publicado em 02 de julho de 2018, 02:13 MANHÃ por dan_johnson dan_johnson | 3 comentários | Deixar um comentário

11 de maio de 2018

How to photograph crayfish for iNaturalist

How to photograph crayfish for inaturalist

In order for crayfish to be adequately identified, it is helpful to provide
a variety of views of the crayfish. Dorsal and lateral views should be
always provided:

In the dorsal view, make sure both the areola and rostrum are
visible:

Lateral view:

Of utmost importance for many species are photos of the gonopod (for
males) or annulus ventralis (for females).

The following image shows the ventral view of an adult male crayfish.
The gonopods are its reproductive organs. They are normally tucked
between the walking legs.

It will often be necessary to pry one into
view with a toothpick or probe. The most useful views are from a
lateral or mesial aspect.

Try to get a closeup view clearly showing the features at the tip:

The following is an image of the ventral side of a female. A closeup
photo of annulus ventralis is very helpful (small round feature between
the last two pairs of walking legs).



Try to get a clear closeup of the annulus ventralis and surrounding area
as follows.

Additional views that may be helpful for identification include:

The chela (claw)

Any hooks present in adult males

The tail fan

Publicado em 11 de maio de 2018, 06:12 TARDE por dan_johnson dan_johnson | 11 comentários | Deixar um comentário

08 de setembro de 2017

cidadas and inaturalist

40 years ago when I was in my mid teens living in Arlington, Texas, I would climb trees to collect the various cicada species calling in the area. Back then there was seemingly no way possible to even remotely identify anything, but it was nevertheless interesting to see the different varieties. Fast forward to today, a young person would easily get all of the species identified by posting them on inaturalist.

I find my interest in cicadas rekindled to some extent and am enjoying learning all the different species that occur in Texas.

Publicado em 08 de setembro de 2017, 04:44 TARDE por dan_johnson dan_johnson | 3 comentários | Deixar um comentário

18 de agosto de 2017

iNaturalist observer bias

The crayfishes Procambarus clarkii and Fallicambarus fodiens are approximately equally abundant in Texas, yet currently there are fifty times more clarkii observations (257 vs. 5).

https://www.inaturalist.org/observations?place_id=18&quality_grade=any&taxon_id=51221

https://www.inaturalist.org/observations?place_id=18&quality_grade=any&taxon_id=100848

The difference is that clarkii inhabits areas such as ponds, lakes and streams where they are likely to be seen by humans, whereas fodiens occurs more in ditches and field, and spends most of their time hidden in burrows.

Publicado em 18 de agosto de 2017, 03:28 TARDE por dan_johnson dan_johnson | 1 comentário | Deixar um comentário