Το Ημερολόγιο του Pardosa lapidicina group

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.

Αναρτήθηκε στις Σεπτέμβριος 28, 2021 0422 ΜΜ από 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

Αναρτήθηκε στις Σεπτέμβριος 26, 2021 1001 ΜΜ από 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'.

Αναρτήθηκε στις Σεπτέμβριος 24, 2021 1215 ΜΜ από eaneubauer eaneubauer | 0σχόλια | Αφήστε ένα σχόλιο

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.

Αναρτήθηκε στις Σεπτέμβριος 03, 2021 0255 ΜΜ από eaneubauer eaneubauer | 0σχόλια | Αφήστε ένα σχόλιο

Αύγουστος 25, 2021

Travis County

I photographed 12 lapidicina group spiders near the upper and lower McKinney Falls in Travis County. They were lighter than the ones from Williamson, Milam, and Bell Counties although some from below the upper falls had stronger banding and one was a darker brown. Most others were without gray or black except for the leg bands. However, considering the ranges of appearance of each county group I failed to find any consistent characteristics to indicate more than one species was involved.
Each population was slightly different on average. Those from Williamson had the greatest contrast and variety of colors looking somewhat reminiscent of P. lapidicina in the southeast U.S. Those in Travis tended to be the lightest with the least variety of color. For now it seems all are probably P. mercurialis and the search for P. vadosa will have to move farther west.

Αναρτήθηκε στις Αύγουστος 25, 2021 1227 ΜΜ από eaneubauer eaneubauer | 3σχόλια | Αφήστε ένα σχόλιο

Αύγουστος 15, 2021

Pardosa lapidicina U.S. tour

Identification of species has two faces. It is as important to know what the organism is as what it isn't. Both are required to confidently identify it because we know that some species are easily mistaken for others. Species identification in the Pardosa genus in general and the lapidicina group in particular has long relied on microscopic examination of genitalia rather than general appearance, colors, and patterns. Almost no attention is been given to macroscopic features and it's rare to find a scientific paper with an image of a live spider let alone an array of photos at different stages of development which would be necessary for making reliable macroscopic identifications in the field or in front of the computer.

Using the process of elimination only works if we know what all our options are, and for that we often look at range maps. Looking at the various published maps for the lapidicina group shows a single species, P. lapidicina, standing alone in the eastern half of the county. Since the lapidicina group is relatively easy to recognize from general photographs, it makes for an easy species identification there despite a variety of forms ranging from very pale to brown or black. No lapidicina group species are shown for about half of the eastern states, but looking at observations at iNaturalist shows them in many of those. Clearly, their range hasn't been fully explored. This didn't surprise me since my search for lapidicina group spiders in central Texas showed them numerous in widely scattered locations and rather particular about their habitat. In fact, I had to work pretty hard to find them at all. I eventually decided they were all Pardosa mercurialis.

As I started trying to establish what my local species options were, I noticed there were no lapidicina group observations at iNaturalist from a large block of counties in eastern Texas. It was impossible to know if they were there but had been overlooked so far. I looked in Louisiana and found nothing. I looked in Mississippi and found nothing. At least P. lapidicina was supposed to be there according to the literature. I looked in Alabama and finally found some lapidicina group individuals. P. lapdicina is the only option. The principal form is an attention getter with patches of black and near white in a messy checkerboard pattern. I was able to find similar spiders in other southeastern and mid-atlantic states. By the time I got to New England, the principal forms were drabber and darker. All could reasonably be identified as P. lapidicina since it was the only known option. About this time I noticed my local mercurialis were yellow on top of the trochanter, a short, mostly bare segment at the top of the leg which is often visible in images at iNaturalist. I also noticed that lapdicina was black in the same place. Finally a clue that might help to tell the species apart!

I continued to search westward to the limits of the published range for lapidicina along the eastern slopes of the Rocky Mountains and down to Oklahoma which was supposed to only have mercurialis. Observations at iNaturalist suggest that was generally true. I found some apparent mercurialis farther north comingled with apparent lapidicina. I ran into a problem with the lapidicina group spiders along both sides of the Mississippi River where the principal form was dark brown with muted markings. Spiders which were fairly similar came with either yellow and black trochanters making this clue appear unreliable in the region. Of course, this needs further investigation

Although I originally had lapidicina as one of my local options, my virtual lapidicina tour helped me conclude they weren't in Texas after all and strengthened my species identification of mercurialis.

Αναρτήθηκε στις Αύγουστος 15, 2021 1132 ΠΜ από eaneubauer eaneubauer | 3σχόλια | Αφήστε ένα σχόλιο

Αύγουστος 12, 2021

The spiders of catherine_g

These got me excited when I first found them at iNat. It was early days in my studies and the images were good quality and numerous. At that time, I had only located one population of lapidicina group spiders myself and was just getting started recording body lengths and ventral views. Now I'm sure enough to do a species ID for them. Although she also observed other Pardosa species, none besides these were in the lapidicina group. Hers are redder than usual, probably as an adaptation to the red rocks in their habitat. You can see a range of appearances. Some have annulated legs, others don't. Some are a lot darker with few markings. This diversity appears typical of most lapidicina group species and obviously makes identification difficult. I've come to believe in identifying them as populations rather than individuals.

Nevertheless, it is possible to find some common characteristics. I've started compiling them and after they are thoroughly tested, I will publish them here. In the matter of lapidicina vs. mercurialis, I'm finding the dorsal color of the trochanter a useful characteristic which shows the importance of good photographs. In addition, I found the dorsal images of specimens preserved in alcohol at BugGuide useful in understanding what I was seeing on the live spiders. Preservation tended to make the hairs transparent so I could see what the surface of the exoskeleton looked like. Hairs get mussed up and knowing what was underneath helped me interpret the patterns better. There were no identified live spider images of mercurialis at BugGuide, so I uploaded a male and a female.

All is not well among the Central Texas lapidicina group spiders. Although most are undoubtably mercurialis, a few I've observed in Bell County don't seem to fit. Going through catherine_g's spiders where there was apparently only one species will help me decide whether they are a different species or not. Pardosa vadosa has been reported in Central Texas, and I always worry about P. sura since there is no trustworthy range or photo for that species.

Αναρτήθηκε στις Αύγουστος 12, 2021 0745 ΜΜ από eaneubauer eaneubauer | 0σχόλια | Αφήστε ένα σχόλιο

Ιούλιος 18, 2021

Species in Eastern and Central Texas

There are perhaps 3 lapidicina group species in eastern and central Texas, specifically lapidicina, mercurialis, and vadosa. The following link shows the ranges of these species according to Barnes, 1959:
http://eaneubauer.ipower.com/lapidicina+mercurialis+vadosa.jpg
Clearly the ranges are incomplete as there are iNat observations of lapidicina group species in eastern Texas and other Gulf States as well. An additional 3 species can possibly be found in the Trans-Pecos region, specifically sura, steva, and valens. Barnes reported sierra and vadosa there. The former were presumably incorrectly synonymized sura. Pardosa steva and valens were reported across the border in both New Mexico and Mexico, so there is a good chance of them being in the Trans-Pecos.

Αναρτήθηκε στις Ιούλιος 18, 2021 0935 ΜΜ από eaneubauer eaneubauer | 0σχόλια | Αφήστε ένα σχόλιο

White Flint Park July 13, 2021

I parked near the boat ramp at the southeast corner of the park in the morning. The temperature was mild and it was mostly sunny. I found three significant habitats in the immediate area. There was a small raised plateau with sparse vegetation, a long, low limestone bluff along the lake, and a small gentle sloping muddy area next to the lake. The last had recently been underwater and was now covered with low vegetation hosting a large number of caterpillars.
A large number of adult Pardosa lapidicina group spiders were seen on the bluff. They appeared to represent a single species which showed obvious sexual dimorphism. The females had banded legs and were pale tan and darker gray overall. The males had fainter leg banding and were a darker reddish brown overall. Their bodies had patches of lighter, yellowish-tan hairs. The cymbium on the pedipalp was claw shaped and dark brown in color.
Many smaller Pardosa representing at least two additional species were found on the plateau and muddy slope along with two late juvenile females of the lapidicina group species. The lapidicina group juveniles were lighter than the adults and in shades of gray with a slight tan tint.
The spider distribution may have been a matter of food availability. The bluffs were largely unvegetated, however there were numerous Pygmy Grasshoppers. The vegetation of the other two areas supported a greater diversity of small arthropods that may have appealed to smaller spiders.

Each location has its own benefits. In this case a single lapidicina group species was apparently isolated, and I have a good selection of both male and female adults photos to work with. This is probably the best place yet for me to try for a species identification. Like most of the lapidicina group species, the male and female had similar body lengths of about 0.25". Two gravid females were obvious exceptions with body lengths of about 0.34". Females with egg sacs had returned to their original lengths. Lengths provided in the scientific literature often show a much wider range of female length, and this is probably why. Carapace length would be a more consistent measure, and the plasticity of the abdomen suggests that reporting body length to a hundredth of a millimeter is overkill.

Αναρτήθηκε στις Ιούλιος 18, 2021 0212 ΜΜ από eaneubauer eaneubauer | 1 σχόλιο | Αφήστε ένα σχόλιο

Ιούλιος 16, 2021

Texas species timeline

Many scientific articles can be found at World Spider Catalog but they have to be read with the understanding of author at the time. For example, the original description of mercurialis won't have any comparative notes on the 4 species described subsequently. The range shown for sierra in 1959 is invalid because Barnes incorrectly synonymized atromedia and sura with it. Another problem is that specimens preserved in alcohol were used to write most of the early pattern and color descriptions and have limited value for identifying live spiders. The 7 species below include all that either have been reported in Texas or are in adjoining states and might be in Texas.

1885 Pardosa lapidicina; original description by Emerton, specimens from Massachusetts and Connecticut
1898 Pardosa sierra; original description by Banks, specimens from Baja California
1904 Pardosa mercurialis; original description by Montgomery, specimens from Austin, TX
1941 Pardosa sura; original description by Chamberin & Ivie, specimens from California
1955 Pardosa steva; original description by Lowrie & Gertsch, specimens from Wyoming
1959 Pardosa sura wrongly determined to be a synonym of sierra by Barnes
1959 Pardosa vadosa; original description by Barnes; specimens from Arizona
1959 Pardosa valens; original description by Barnes; specimens from Arizona
2010 Pardosa sura; restablished as a species by Correa-Ramirez, Jimenez, & Garcia

Pardosa sierra is almost certainly not in Texas
Pardosa sura is almost certainly in west Texas
Pardosa valens is likely in west Texas
Pardosa steva might be in west Texas
Pardosa atromedia, a California species, was also wrongly synomymized with sierra and later restablished as a species.

Αναρτήθηκε στις Ιούλιος 16, 2021 1053 ΠΜ από eaneubauer eaneubauer | 0σχόλια | Αφήστε ένα σχόλιο

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