Phyciodes tharos, DISTINCTA BAUER (1975)

Pavulaan, Harry, 2023, Examination of the status of Phyciodes tharos distincta Bauer, 1975, confirming it as a valid subspecies., The Taxonomic Report of the International Lepidoptera Survey 11 (4), pp. 1-11 : 2-8

PHYCIODES THAROS DISTINCTA BAUER (1975) , ORIGINAL DESCRIPTION

Miller & Brown (1981) stated, quite eloquently: “This name is another proposed by Bauer in a rather unsatisfactory manner. In this instance the type-locality is given, but no types are designated, nor are they figured.” The original description by Bauer (in Howe, 1975) follows:

(b) distincta Bauer. This subspecies has a complete pattern of fine lines on the upper surface, is very constant in wing pattern above, and rarely has the blotchy, irregular appearance so common in individuals of tharos tharos . The cool weather form is scarce and appears only during midwinter over most of its range. Similar individuals appear in colonies of typical tharos , and there is a broad blend zone of the two populations in Texas and northeastern Mexico.

Distribution: The type locality is Calexico, Imperial county, California. This is a predominantly Mexican subspecies, ranging south to the Sierra Madre del Sur and occurring in the United States along the lower Colorado River north to Moab, Utah, and in a blend zone with nominate tharos from southeastern Arizona into Texas.

A holotype was not designated in the original description of P. tharos distincta (ref. ICZN Article 73.1.3). The supposed holotype reportedly residing in the collection of the Natural History Museum of Los Angeles County ( Ferris, 1989, Scott, 1998) was not found per Weiping Xie, Collections Manager, Natural History Museum of Los Angeles County (pers. comm.), though there is a unit tray labelled as all “paratypes” ( Fig. 1). However, these cannot be treated as paratypes as the yellow note indicates they were designated by Bauer on 4-13-1982; and at least 8 of the males (rows 2-4 from top) cannot be paratypes as they were collected during the period of Sept. 12-15, 1982. The older specimens in row 1 may be syntypes. No specimens in the unit tray actually bear “ paratype ” labels. However, Nick Grishin (pers. corr.) photographed two specimens labelled as “ paratypes ” ( Figs. 2 & 3) in the collection of the McGuire Center for Lepidoptera and Biodiversity. Discussion with Crispin Guppy (pers. corr.) suggests that, since no holotype was designated in the original description of distincta , these are all syntypes (ICZN Article 73.2) from which a lectotype can be designated (ICZN Article 74.1).

I designate the specimen in Fig. 2 as LECTOTYPE of Phyciodes tharos distincta Bauer, 1975 with the following data: California, Imperial County, Calexico, May 5, 1934, leg Lloyd M. Martin; det. D. L. Bauer; ex-D. Bauer collection via J.D. Turner collection; MGCL Accession # 2010-29 ; DNA sample ID: NVG-21067H12 , c/o Nick V. Grishin. The specimen resides in the McGuire Center for Lepidoptera and Biodiversity.

SUBSEQUENT (POST-1975) TREATMENT IN THE LITERATURE

Miller & Brown (1981) treated distincta at subspecies rank.

Hodges (1983) treated distincta at subspecies rank but emended the name to distinctus per the ICZN.

Tilden & Smith (1986) interestingly, did not include P. tharos for the western states. Rather, they treated populations in southeastern California east to western Texas and Mexico as subspecies P. pascoensis distinctus .

Ferris (1989), under species entry 161:623c commented: “To conform to the CODE, emend spelling to: distinctus.” [This emendation has not been adopted by some subsequent authors.] Ferris treated distinctus at subspecific rank. However, Ferris made an interesting comment: “In south-central Wyoming and along the Arizona-New Mexico border, there are tharos populations that will probably prove to be distinct species (C. G. Oliver, in litt.).”

Bailowitz & Brock (1991) treated southeastern Arizona tharos as ssp. tharos , but commented: “True tharos , which occurs at least in southern Arizona, has its subspecific taxonomy in confusion as well. Material from the region appears most like nominotypical tharos and less like distincta Bauer. ” They give the habitat as “agricultural and riparian areas, occasionally from the more wooded canyons”. Early/late flight dates are Mar. 22 to 13 Nov.

Brown, et al. (1992) treated distincta at subspecies rank.

Scott (1992) stated: “ …distincta Bauer (type locality Calexico, Imperial Co., Calif.) is a synonym of tharos (unless distincta is used for the southern populations with white-and-black antenna clubs, tharos for northern populations with orange-and-black antenna clubs), and even tharos from central Mexico do not differ appreciably from SE U. S. tharos.” [The present paper opts to follow Scott’s assertion: “ …distincta is used for the southern populations with white-and-black antenna clubs”, though the range is more restricted to the SW U.S.].

Scott (1994) stated: “The name distincta Bauer (1975) (figs. 86-89), type loc. Calexico, Imperial Valley Calif., is a synonym of tharos based on the series of adults I examined. The unf black spots appear to be a little smaller than typical tharos, and one female (fig. 89) has somewhat less black ups markings than typical tharos, and one female has the tip of lamella paraostialis a little more rounded than tharos and more like riocolorado, but distincta is closer to tharos than to riocolorado in wing pattern and genitalia, so I treat distincta as a synonym of tharos; at best it is a weak ssp. for splitters.” Scott illustrated “syn. “distincta ”” with specimens from Calexico and Brawley, CA., on page 113. [The few male specimens of Utah riocolorado in my possession are practically identical to ssp. tharos males ( Fig. 7), contrary to Scott’s assertion, whereas distincta is recognizably different from both. See comments below.] Scott, citing Bailowitz & Brock (1991) listed the host as A. subulatus var. ligulatus in Arizona. However, Bailowitz & Brock (1991) listed the host as Aster exilis , a nomen dubium revised as Symphyotrichum divaricatum (USDA, 2022) .

Scott (1998) simply listed, in the synonymy of tharos species-group: “= distincta Bauer, 1975, type LACM (=Natural History Museum Los Angeles County) ( Ferris, ed., 1989).”

Emmel, et al. (1998) listed distinctus at subspecific rank in their California checklist.

Austin (1998) listed distinctus at subspecific rank in the Nevada checklist.

Bailowitz & Brodkin (2007) gave the following habitat description for P. tharos : “This is a species of riparian areas, predominantly in the southern reaches of the state. It frequents permanent watercourse edges, lakesides, and cienegas [permanently saturated, alkaline, freshwater, spongy, wet meadows], especially those with asters, beggarticks, and buttonbush.”

Pelham (2008 -2023) listed distincta as a junior synonym of P. t. tharos and comments: “Location of holotype not known”.

METHODOLOGY

Color analysis was performed using the Color GrabTM cellphone application (www.loomatix.com), version 3.9.2, to establish exacting RGB and HSB color codes under “daylight” fluorescent lighting, in combination with the ColblindorTM application (www.colorblindness.com/color-name-hue/) to produce refined color swatches rather than giving generalized color descriptions as is traditional with taxon descriptions. Two different areas of the wings were measured for their red/green/blue (RGB) and hue/saturation/brightness (HSB) color codes. Ground color was measured on the dorsal hindwings, which showed a more consistent, stable color in each of the two series (dorsal forewing color showed slight variation between the postmedian ground color vs. remainder of the dorsal wings, on different specimens). Darkness of the black pattern in each series was performed on the outer portion of the forewings either near the apex or tornus. The ventral surfaces were not analyzed, due to considerable variation across both subspecies. 300 males and 196 females of subspecies tharos from many areas of eastern North America (N.C., VA., W. V., MD., N.Y. and R. I.) were analyzed, while 50 males and 31 females of subspecies distincta (all from Santa Cruz Co., AZ.) were analyzed. All specimens were of summer phenotypes [sufficient numbers of spring specimens of distincta were not available]. Color codes of individual specimens were then averaged to produce results for each subspecies ( Fig. 4). Color names in the description of each of the four species references the color names given in the Color GrabTM and ColblindorTM applications. Of particular interest are the differing results of the color analysis vs. visual comparisons. While the human eye perceives a decidedly paler overall appearance in distincta ( Fig. 5), the color analysis tools show fairly similar colors in the two areas examined ( Fig. 4). The color analysis tools do, however, reveal a difference in ground color and slight difference in “blackness” of the wing patterns, between series of females. Males of both subspecies are fairly similar. The comparisons are made between specimens of “fresh” condition.

Additionally, wing measurements were made from the examined series. Measurements were made of forewing length ( Fig. 4). These were then averaged and a range and mode for each was determined. Interestingly, specimens of distincta showed more consistent measurements, while tharos showed considerably more variation in wing measurements.

PHENOTYPIC COMPARISON

Southern Arizona distincta differs from eastern nominotypical tharos as follows:

Size. Male distincta are slightly smaller than nominotypical tharos ( Fig. 4). The length of the male forewings of the examined distincta series ranges 13-16 mm, averaging 14.5 mm, whereas eastern U. S. tharos males averaged larger, ranging 12-19 mm, averaging 15.6 mm. The mode was, interestingly, similar at 15 mm for both subspecies. Female distincta are larger than males, ranging 15-18 mm, averaging 16.5 mm, whereas eastern U. S. tharos females averaged slightly larger, ranging 15-20 mm, averaging 17 mm. The mode was also similar at 17 mm for both subspecies.

Dorsal ground color. The ground color of distincta males and females is generally a concolorous brown-orange (“ Peru ” in males, “Golden Bell” in females) ( Fig. 4), whereas the ground color of tharos males and females is generally more orange than brown (“Ochre” in males, “Fire Bush” in females). Some females show a very slight amount of lighter ground coloration in the postmedian area of the forewings. Visually, the ground color of nominotypical tharos in the eastern U.S. is a brighter orange than distincta , which has a paler look ( Fig. 5). This is less apparent in the males, but more apparent between females of both subspecies. [Interestingly, the color analysis tools did not pick up the intensity of the dark patterns, rather just the base color.

Dorsal pattern and color of markings. The wing markings of distincta males and females are dark (“Cocoa”) brown ( Fig. 4). Males of nominotypical tharos are similarly dark (“Cocoa”) brown, whereas females are a blackish (“Livid”) brown. Visual comparison of the wings reveals that the wing markings of distincta are distinctly paler, giving a more brownish look compared to nominotypical tharos , on which the wing markings are black and sharp. In distincta , the postmedian orange band in the males is generally more broken than in tharos , whereas tharos males have a more continuous band. In distincta the pattern of markings is more consistent, and not as variable as in tharos . In nominotypical tharos , the postmedian line on the male hindwings is variably developed and often broken in mid-section, washed out by the orange ground color. Distincta males always have this postmedian line fully-developed. In nominotypical tharos , the males have a wider marginal wing pattern, giving a darker appearance, whereas, in distincta the outer wing pattern is narrower, giving specimens a lighter overall appearance. The contrast between females of both subspecies is striking ( Fig. 5). Nominotypical tharos females generally have heavier infuscation on the basal portion of the forewings, giving specimens a considerably darker appearance, whereas in distincta females, this infuscation is generally lacking and the underlying pattern is more visible, giving them a lighter appearance. In general, distincta has a pallid appearance, compared to nominotypical tharos .

Ventral color and pattern. The general appearance of the ventral hindwings of distincta males is somewhat paler than in nominotypical tharos , though coloration is highly variable in both ( Fig. 6). Male tharos have a more extensive, brighter orange wash on the forewings, whereas in distincta this feature is somewhat broken up by a subdued, weblike pattern. The black pattern on the outer portion of the ventral forewings is darker and more developed in nominotypical tharos . The females of both subspecies display similar, highly variable coloration and pattern. The only appreciable difference between adults of nominotypical tharos and distincta is in the brown marginal patch of the hindwings. In distincta this patch is of a paler browner shade, whereas in nominotypical tharos it is generally darker brown. This is more evident in the males.

Wing shape. While variable, the outer margin of the forewings of nominotypical tharos tend to be more rounded, whereas the outer margin of distincta is straighter, appearing slightly concave in some specimens. This is more noticeable in series of males ( Fig. 5).

DISTRIBUTION

The range of distincta has yet to be refined and requires further study. Based on literature sources, specimen series and images posted to butterfliesofamerica.com (accessed 16 Jan. 2023) and iNaturalist.org (accessed 16 Jan. 2023), the range in the United States can be defined primarily as extreme southeastern California (Imperial, Riverside and San Bernardino Counties) and south-central Arizona (Pima, Santa Cruz and Yuma Counties). Most records are clustered south of Tucson to the Mexican border. In Arizona, individuals in Cochise and Graham Counties show intergradation to nominotypical tharos . All New Mexico records appear to be nominotypical tharos with some individuals appearing slightly intermediate to distincta . All of Texas appears to be within the range of nominotypical tharos . In Mexico, distincta is reported from the state of Baja California (Baja California Norte). Images posted to butterfliesofamerica.com show candidate distincta specimens down the west side of the northern half of Mexico, in Sonora and Nayarit states, essentially west of the Sierra Madre Occidental. However, examined images in iNaturalist indicate all other Mexican populations east of the Sierra Madre Occidental and in the southern half of Mexico are closer to nominotypical tharos . Thus, distincta is confined to a very small range along the California and Arizona border with Mexico, and possibly south along the Mexican Pacific Coast region, and may be considered an endemic of the region.