Aphredoderus retrodorsalis, Muller & Simons, 2024

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 : 91-93

Aphredoderus retrodorsalis sp. nov.

Lowland Pirate Perch urn:lsid:zoobank.org:act:9DF376E9-1EE9-43AA-9DAD-5F768841D3DF

Figure 7 , 11 ; Tables 3 , 7

Holotype: JFBM 50272 : 50.5 mm SL, Rice Creek at Bardin Road, 6 miles WNW of Palatka, Putnam County, Florida, U.S.A. (29.69, -81.72) 5-Jul-2022.

Paratopotypes: (2 specimens, 46.8–51.1 mm SL) Same locality and date as holotype. JFBM 50548 (1) , NCSM 113083 (1).

Paratypes: (77 specimens, 28.7–88.6 mm SL).

Alabama: Escambia County: UAIC 4969.06 (5). Florida: Baker County: UF 176117 (1), UF 26335 (3). Bradford County: JFBM 50541 (6), JFBM 50229 (3). Gadsden/Leon County: UAIC 12602.05 (3). Gilchrist County: UF 58218 (3), Gulf County: UF 120412 (1). Hamilton County: UF 57219 (5). Leon County: JFBM 50540 (1), Liberty County: JFBM 50232 (2), JFBM 50233 (5), UF 144290 (2). Okaloosa County: JFBM 50221 (1), JFBM 50538 (4), JFBM 50539 (1). Putnam County: JFBM 50273 (1), JFBM 50548 (1). Santa Rosa County: UF 174431 (3), UF 177095 (4). Union County: JFBM 50542 (1) Walton County: UF 145076 (1). Georgia: Brooks/Lowndes County: UF 144794 (1). Colquitt County: UF 54005 (1). Wheeler County: JFBM 50536 (11), JFBM 50537 (2).

Diagnosis: This species differs from A. sayanus and A. ornatus by having three vs. four dorsal spines, and in having higher mean scale counts; in lateral series 46 vs. 42–44, rows above lateral line 9 vs. 8, and further from A. ornatus by caudal peduncle rows (33 vs. 29). Where sympatric with A. ornatus this species also differs by caudal markings (bar vs. spots) and by having a longer postorbital length. This species additionally lacks the ventrolateral caudal peduncle stripe seen in A. ornatus . From A. gibbosus , this species differs in having a larger eye (mean 26% HL vs. 23.9%), narrower interorbital space (mean 92.9% in orbit vs. 77.8%) and typically by having a caudal bar rather than two caudal spots. From A. mesotrema , this species differs in having a smaller orbit (mean 26% HL vs. 28%), longer postorbit (mean 16% SL vs. 13.9%) and long caudal bar or indistinct caudal markings compared to a short caudal bar ( Fig. 11 ).

Description: Dorsal, III:11 (III:11/12). Anal, III:6 (III:6/7). Pectoral Rays 11 (10–11). Lateral scales 46 (43– 49), scale rows above lateral line 9 (8–10), caudal peduncle scales 34 (30–37). Body depth regionally variable average into SL is 29%, though Westernmost and Georgia species frequently taller-bodied. Head longer, 33% of SL. Postorbital length long, typically 16% of SL. Caudal depth average, about 15% of SL. Predorsal longer, about 47% of SL. Eye large, usually close to 26% of HL. Interorbital space narrow, orbit approximately 93% of interorbital size.

Coloration: Black to dark brown or reddish brown. Caudal markings may consist of two chevrons or a caudal bar extending nearly the height of the caudal peduncle ( Fig. 11 ). Abdomen heavily pigmented.

Distribution: Gulf of Mexico drainages in Florida and Alabama from the Blackwater River to the Suwannee-Santa Fe River system, though absent in many Springs South and East of the Ochlocknee River, except for the lower Suwannee River where it is probably present ( Fig. 10 ). Likely absent in Chattahoochee and Flint Rivers, though present in the Apalachicola River. On the Atlantic slope this species is present from the Saint Johns River North to the Ogeechee River in Georgia. This species is commonly syntopic with A. mesotrema and A. ornatus .

Etymology: The specific epithet retrodorsalis refers to the insertion of the dorsal fin (Latin = dorsalis) behind (Latin = retro) the apex of the back. The common name of this species reflects the observation that this species occurs at lower elevation than other Southeastern Aphredoderus .

Figures

FIGURE 7. Aphredoderus retrodorsalis, JFBM 50272, holotype from Rice Creek (tributary to the Saint Johns River), Putnam County, Florida, 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.