Aphredoderus mesotrema, Jordan

Muller, Tyler A. & Simons, Andrew M., 2024, Taxonomic revision of the Pirate Perches, Aphredoderus, (Percopsiformes: Aphredoderidae) with descriptions of two new species, Zootaxa 5415 (1), pp. 77-105 : 89-91

Aphredoderus mesotrema ( Jordan 1877a)

Figure 6 , 11 ; Tables 3 , 6

Asternotremia mesotrema Jordan 1877a: 81–82. Tributary of the Flint River, Taylor County, Georgia, U.S.A. Unknown collection date.

Holotype: USNM 9296 (lost): Flint River , Taylor County, Georgia, U.S.A. Paratypes: USNM 20497 . Little Red River , Arkansas .

Neotype: JFBM 50011 : 61.9 mm SL, Sandy Mount Creek at GA-90 overpass, 2.7 miles NW of Vienna, tributary of the Flint River, Dooly County, Georgia, U.S.A. 16-Jul-2021.

Other material: (179 specimens, 25.6–83.3 mm SL).

Alabama: Baldwin County: UAIC 34549.01 (3). Covington County: UAIC 3552.04 (1), UAIC 4192.06 (1), UAIC 4971.09 (2). Elmore County: UAIC 14686.05 (1). Mobile County: UAIC 34525.01 (2), UAIC 36150.01 (1). Russell County: JFBM 50009 (8), JFBM 50010 (11). Florida: Bay County: JFBM 50228 (2), UF 132228 (1). Calhoun County: JFBM 50230 (5). Escambia County: JFBM 50219 (2). Gadsden County: JFBM 50231 (8), UF 52159 (1). Leon County: JFBM 50234 (8). Liberty County: JFBM 50232 (1). Okaloosa County: JFBM 50222 (7), JFBM 50223 (13), JFBM 50224 (1), JFBM 50225 (1), JFBM 50226 (3), UF 175010 (4). Santa Rosa County: JFBM 50220 (6), UAIC 3032.1 (2), UAIC 3141.04 (1), UAIC 4987.04 (1), UAIC 6769.07 (4), UAIC 6770.07 (2), UF 103972 (4), UF 138470 (1), UF 145012 (4), UF 174431 (2), UF 177095 (16). Walton County: UAIC 5243.02 (1), UAIC 5276.01 (1), UF 142288 (5), UF 145076 (2), UF 145237 (1). Washington County: JFBM 50227 (5). Georgia: Clay County: UF 105232 (2), JFBM 50012 (6). Dooly County: JFBM 50547 (2), NCSM 113082 (2), UF 249617 (2). Early County: NCSM 28080 (2). Stewart County: UF 103257 (3). Talbot County: UF 103397 (4). Thomas County: UF 172736 (2).

Diagnosis: Aphredoderus mesotrema differs from A. sayanus and A. ornatus by having three instead of four dorsal spines and higher mean scale counts; in lateral series 49 vs. 41–44, and in rows above the lateral line, 10 vs. 8. This species is further differentiated from A. ornatus in caudal peduncle scale rows, 33 vs. 29, and the absence of a lateroventral stripe. From A. sayanus , this species also has heavily vs. lightly pigmented abdomen. From all but A. ornatus , this species is most readily differentiated by its short post opercular length (mean 13.9% SL vs. 16.0%– 16.5%), and large orbit (mean 29.7% HL vs. 23.9%–28.0% From A. gibbosus , this species has a much narrower orbital area (mean 91.9% of orbit vs. 77.8%). From all but A. ornatus , A. mesotrema contains a caudal bar rather than spots or chevrons. When compared to caudal markings on A. retrodorsalis , the caudal bar is shorter ( Fig. 11 ).

Description: Dorsal, III:11 (III:10/12). Anal, III:6 (II/III:6/7). Pectoral Rays 11 (11–12). Lateral scales 49 (47– 51), scale rows above lateral line 10 (9–11), caudal peduncle scales 33 (31–35). Body depth average to slender (29% of SL). Head length short, 31% of SL. Postorbital length short, almost always shorter than 15% of SL. Caudal depth variable. Predorsal length average, nearly 46% of SL. Eye large, 28% of head length. Interorbital space narrow, orbit approximately 92% of interorbital size.

Coloration: Black to dark brown or reddish brown. Short black vertical bar over hypural. Abdomen moderately to heavily pigmented ( Fig. 11 ).

Distribution: Flint and Chattahoochee River below fall lines, and coastal drainages in the Eastern Gulf of Mexico from the Escambia River in Western Florida to the Ochlockonee River near peninsular Florida ( Fig. 10 ). We also observed this species in the Tallapoosa River, and a tributary to the Mobile River, though this species does not appear widespread in this basin. This appears to be the only Aphredoderus species in the Flint and Chattahoochee River systems.

Notes: Jordan described this species based on its vent being “about an eyes length” anterior to its ventral fin insertion unlike the more posterior vent in Sternotremia isolepis . Beyond this character, Jordan briefly described this species as having 45 lateral line scales, three dorsal spines, eight dorsal rays, three anal spines, 7 anal rays and a head shorter than 1/3 rd the length of the fish and noted the specimen was in poor condition. Jordan designated paratypes from the Little Red River in Arkansas to supplement his description. One year later Jordan suggests that the vent location is due to life stage and synonymizes this species with Aphredoderus sayanus ( Jordan 1878). These observations offer little guidance except for excluding A. ornatus and A. sayanus by count of dorsal spines. Further complicating diagnosis of this species is Jordan’s designation of specimens from Arkansas as paratypes. While these paratypes are also lost, we examined a remaining plate ( Jordan 1877a), and this is undoubtedly A. gibbosus due to caudal spots, small eye size and dorsal fin placement and does not represent any species known to occur in Georgia.

In his species description Jordan references USNM lot 9296 and only gives Georgia as a locality and attributes this specimen to a collection by Dr. Hugh M. Neisler. A year later, the locality was refined to the Flint River drainage in Taylor County, Georgia without explanation ( Jordan & Brayton 1878). This lot is said to include Campostoma anomalum , Pteronotropis grandipinnis and Semotilus thoreauianus . In more recent taxonomic works on the latter two species, authors refer to this locality ( Johnston & Ramsey 1990; Suttkus & Mettee 2001).

We requested information from the USNM about lot 9296 and were informed no Aphredoderus or Asternotremia were associated with the lot after a thorough search through both genera on the shelves and through remaining jars from USNM 9296. When checking museum records, type specimen manager Erika Wilbur found lot 9296 had first been attributed to C. anomalum and at some point, the taxonomy had been replaced with S. thoreauianus and the locality data remained with the new taxonomy and C. anomalum was re-cataloged to USNM 170695. Wilbur suggested that the locality data of “ Georgia ” belonging to USNM 9296 is only that of C. anomalum and the remaining species cataloged under this lot are of doubtful collector and locality (Erika Wilbur, pers. comm. Feb 1, 2023). In a taxonomic study of Pteronotropis grandipinnis ( Suttkus & Mettee 2001) , the authors searched for type material to no avail, although they were able to locate a letter from Dr. Neisler describing his discovery of the species. The letter did not identify the collection locality and the authors choose to designate a neotype from Beaver Creek, a Flint River tributary in Taylor County, Georgia due to the proximity of the Neisler homestead ( Suttkus & Mettee 2001). Unlike A. mesotremia , Jordan’s description of P. grandipinnis was sufficient to distinguish from other species in Pteronotropis .

Poly (2004) declared A. mesotrema as nomen nudum. Reasoning for this conclusion was not provided though given a type specimen was indicated and a formal description was provided, albeit for an immature state, this name remains valid. Aphredoderus mesotrema is a nomen dubium and at present hinders description of remaining Aphredoderus . It is likely A. mesotrema was discarded as it was in poor condition, miscataloged and quickly synonymized into A. sayanus from the type author. It is with little doubt A. mesotrema is missing and we find it appropriate to designate a neotype for A. mesotrema .

The Neisler collection is said to have occurred in the Flint River in Taylor County, Georgia. We chose a specimen from a tributary of the Flint River , Sandy Mount Creek in Dooly County , 37.5 miles SE of the center of Taylor County as this was the closest collection which also contained tissue samples. In this span of the Flint River , there are no significant changes in species assemblages. It is here we assign JFBM 50011 as the neotype for Aphredoderus mesotrema .

Figures

FIGURE 6. Aphredoderus mesotrema, JFBM 50011, neotype from Sandy Mount Creek (tributary to the Flint River), Dooly County, Georgia, U.S.A.

FIGURE 10. Range and sampling locations of Aphredoderus mesotrema and A. retrodorsalis used in this study. Sampling locations with black outlines indicate genetic sampling. Type locality is for USNM 9296, georeferenced to site indicated by Suttkus and Mettee (2001).

FIGURE 11. Morphological Diagnosis of Aphredoderus within the Southeastern United States: A) Principal component analysis of specimens from within the Southeastern Contact Zone from Pensacola Bay tributaries in Florida to the Ogeechee River in Georgia showing complete separation of A. ornatus (+) and strong separation of A. mesotrema (△) from A. gibbosus (O) and A. retrodorsalis (X). B) Southeastern contact zone in Aphredoderus. C) Contrast adjusted images (+ 0–30% brightness, + 40% contrast) to clearly display black pigmentation on caudal peduncle and the ventrolateral stripe present in A. ornatus. From top to bottom: A. gibbosus from Wacissa River in Florida, A. retrodorsalis from the Ogeechee River in GA, A. mesotrema from Choctawhatchee River, FL, A. ornatus from New River, in Florida. D) Characters to identify Southeastern Aphredoderus: Top; Separation of A. retrodorsalis from commonly sympatric A. mesotrema and A. ornatus by postorbital length, Bottom; Separation of A. gibbosus from potentially sympatric A. retrodorsalis by interorbital width and eye size.