Το Ημερολόγιο του Pardosa lapidicina group

Αρχεία Ημερολογίου για Σεπτέμβριος 2021

Σεπτέμβριος 03, 2021

Burleson County

After looking at satellite views, it appeared the closest place the Brazos River could be accessed over public land south of Falls on the Brazos was near the route 21 overpass so I checked it out on 8/30. I was prepared for failure because most places like this turn out to be much too steep or jungle-like to get to the river these days. I was lucky as there was a narrow path up the river on the west side that fishermen were using. The path was about a third of the way up a sandstone bluff and a misstep could have put me in the mud or river at the bottom. I might survive, but my camera probably wouldn't. There wasn't much maneuvering room but I managed to find an photograph 3 small wolf spiders. The first was Pardosda lapidicina group. After getting back home and looking at the photos, it appeared to be Pardosa mercurialis. This was the farthest downsteam in the Brazos watershed anything in the lapidicina group has been observed. The other spiders I field identified as other Pardosa species, but one turned out to be a juvenile Arctosa littoralis. Three spiders, three species. The first spider was on bedrock, the other two were on sand. At Falls on the Brazos there is a gravel beach on the far side of the river. I figured it was prime habitat for Pardosa lapidicina group sometime ago. Finding one downstream makes it very likely they are there, but confirmation will have to wait for low enough water to walk across on the old road.

Posted on Σεπτέμβριος 03, 2021 0255 ΜΜ by eaneubauer eaneubauer | 0σχόλια | Αφήστε ένα σχόλιο

Σεπτέμβριος 24, 2021

In search of P. vadosa

After finding several scattered colonies of mercurialis, the project lost momentum and needs a jolt. The scientific literature shows some vadosa around the Rolling Plains/Edwards Plateau interface. I looked at iNaturalist observations in the area and found one definite non-mercurialis and several possibles. The definite appears to be on private land and inaccessible. My best bet seems to be the area between Menard and Llano along the San Saba and Llano Rivers. I used google maps to locate a number of access points, most of which are in those towns. Although the scientific literature says that vadosa is exceptionally pale I suspect that only refers to preserved specimens. They may look more like iNat 8513419 in real life. Based on the dorsal trochanter pattern this one is not mercurialis.

I also tabulated the number of Lycosid observations for each Texas County. Many are only in the single digits and some have zero. If you visit any of these counties, please check out rocky areas near water for Pardosa lapidicina group. They are active year round in sunny areas or when temperatures approach 80.

Meanwhile I've been accumulating good dorsal and ventral images, male and female, of the palm sized Lycosids on my property which come out after dark. They include Rabidosa rabida (of course), Hogna antelucana, and Hogna 'incognita'.

Posted on Σεπτέμβριος 24, 2021 1215 ΜΜ by eaneubauer eaneubauer | 0σχόλια | Αφήστε ένα σχόλιο

Σεπτέμβριος 26, 2021

Menard County

The results:
https://www.inaturalist.org/observations/96288916
https://www.inaturalist.org/observations/96288910
https://www.inaturalist.org/observations/96288917
https://www.inaturalist.org/observations/96288909

The trip was successful in that I found 3 females at Tenmile Crossing and got good photos.
The trip was unsuccessful in that I found no males, and every other prospective location was either inaccessible, not quite the right habitat, or void of Pardosa. The last included Llano. Perhaps downstream from town I might have been more successful.
So, these do appear to be a different species from mercurials and similar to one observed on private property nearby. Although you'd never figure it from the scientific description, I'm pretty sure these are Pardosa vadosa, and I will be able to work out a functional description for live female spiders at least.

Why is the grasshopper link here? Pardosa are always found with pygmy grasshoppers. I suspect Algae, Paratettix, and Pardosa are part of a year round food chain. The only difference between the lapidicina group species and other Pardosa seems to be a strong preference for streams, rivers, and lakes over ponds and ditches.

Eric

Posted on Σεπτέμβριος 26, 2021 1001 ΜΜ by eaneubauer eaneubauer | 0σχόλια | Αφήστε ένα σχόλιο

Σεπτέμβριος 28, 2021

Menard County spider description and analysis

Based on 3 females, one with egg sac, believed to be Pardosa vadosa based primarily on range. The species are said to be light in color which may be due to the overall covering of pale creamy hairs on these individuals.

Links to my observations:
https://www.inaturalist.org/observations/96288917
https://www.inaturalist.org/observations/96288916
https://www.inaturalist.org/observations/96288910

A probable juvenile from Utah:
https://www.inaturalist.org/observations/13599267

Found in a similar habitat to P. mercurialis which is common farther east in Texas at least as far as the Brazos River and apparently the only lapidicina group species present. As can be seen below, there are enough differences in general appearance, especially ventrally, to conclude that they are different from mercurialis.

Dorsal:
Carapace:
Length/width = 1.15. (same as mercurialis iNat 92392407)
Posterior eyes form trapezoid, base wider than tall (ratio 1.5 same as mercurialis iNat 92392407).
The area in between is black on the exoskeleton. (mercurialis same)
Posterior medial eyes wider than anterior eyes. (mercurialis same)
Posterior eye are more or less bordered with orange. (same as some mercurialis)
Thorax evenly covered with pale, creamy hairs. (same as some mercurialis but color varies in hue)
Border of thorax as mercurialis and lapidicina.
Hairless back of thorax yellowish, darkened especially at lateral black bands. (tends to be more irregular on mercurialis)
Thoracic furrow only visible on exoskeleton. (usually visible on mercurialis)
Abdomen:
Even row of white hairs guarding connection of thorax and abdomen. (tends to be in tufts on mercurialis)
Medial band ovoid, yellowish in front containing 4 brown spots at edge of cardiac area;
the front of this area has a reddish hue on one individual;
remainder of cardiac area light brown edged in dark brown; wine glass shaped;
yellowish tan patches at sides of bowl; pale yellow-cream below bowl;
series of 4 pairs of yellow circles with dark brown centers begin above base and converge
toward back of abdomen; each pair is underlined by a pale yellow-cream chevron;
the base of the cardiac border is directly in front of the 1st chevron.
(on mercurialis ovoid shape not apparent, 4 pairs of circles present but unclear on mercurialis, not yellow;
outline of cardiac area dotted rather than solid))
Chevrons marked with continous lines rather than triplets of pale patches like mercurialis.
Irregular dark brown marks begin at the lower corners of the bowl extend backwards and outwards
ending in barbs which point back at the centers of the first pair of yellow circles.
(dark areas indistinct and shaped differently on mercurialis)
A pair of dark brown patches connect the ends of the 2nd and 3rd chevron. (also present on mercurialis)
These are prominent on the exoskeleton.
Sides of abdomen paler than top.
Legs:
Boldly annulated with 2 less distinct rings mid femur; distal tips of femur, tibia, and tarsus dark;
proximal half of patella slightly darker; 2 bold rings proximal end and mid tibia;
2 rings proximal end and mid tarsus; general appearance of 8 rings.
Dorsal trochanters consistently yellow with thin orange border;
yellow area containing two bullet shaped black patches.
(mercurialis similar but patches are dart shaped and extend to the orange border)
Tarsi burnt orange with black tips. (mercrialis same)

Ventral:
Carapace:
Sternum black with numerous long, pale cream hairs; coxae similar but generally lighter. (mercurialis similar)
Abdomen:
Covered with short pale and occasionally dark hairs.
Area in front of genital furrow covered with pale cream to yellowish hairs.
Remainder has a rosy hue becoming orange then yellow at back; area below spineret very dark brown;
hues extends up to the middle of the abdomen. (hues absent on mercurialis)
(for mercurialis, entire abdomen has white hairs covering a yellow exoskeleton except that in the genital area
the exoskeleton is darker; the rosy to orange hue is absent, and the area around the spinneret is yellow)
Legs:
Mostly gray to black with yellow in between consitent with dorsal rings.
Underside of femora almost entirely dark gray with lighter hairs except for yellow patch with
black border at distal end; very short hairless area at proximal end also yellow.
An additional yellow patch about 2/3rds of the way down the femur I, II, and III but not femur IV;
some of these yellow patches may be from wear.
Underside of metatarsi and tarsi pale orange.
Underside of pedipalps mostly pale yellowish; distal segment is orange with dark tip.
(for mercurialis, underside of femora, trochanters, and coxae, have consistently white hairs covering a yellow
exoskeleton; and in general the underside is paler)
Chelicera:
Very dark brown. (orangish brown on mercurialis)

Note: the female with the egg sac had a lot more dark orange exoskeleton showing. Apparently much of the hair which was
nearly white had been lost. As a result, much of the exoskeleton pattern is visible including the dark brown thoracic furrow.
This made it easier to compare with preserved specimens. P. mercurialis doesn't appear to be affected by hair loss.

Posted on Σεπτέμβριος 28, 2021 0422 ΜΜ by eaneubauer eaneubauer | 0σχόλια | Αφήστε ένα σχόλιο