Stygobromus floridanus Holsinger and Sawicki

Holsinger, John R. & Sawicki, Thomas R., 2016, A new species of the subterranean genus Stygobromus (Amphipoda: Crangonyctidae) from a cave spring in northern Florida, USA, Zootaxa 4067 (1) : -

publication ID

https://doi.org/ 10.11646/zootaxa.4067.1.7

publication LSID

lsid:zoobank.org:pub:5457C07B-A86C-45D3-9BFF-6337AF1CC336

DOI

https://doi.org/10.5281/zenodo.6053432

persistent identifier

https://treatment.plazi.org/id/CC064F40-FFA6-FFE0-DB8A-F94B51EC56B7

treatment provided by

Plazi

scientific name

Stygobromus floridanus Holsinger and Sawicki
status

sp. nov.

Stygobromus floridanus Holsinger and Sawicki View in CoL , sp. n.

Figures 2 View FIGURE 2 , 3 View FIGURE 3 , 4 View FIGURE 4 , 5 View FIGURE 5

Material examined. Holotype female 13.0 mm, 2 female paratypes (8.0 and 9.0 mm) collected by Tom Morris, 12 February 2003, and in addition, 1 juvenile paratype (6.0 mm) specimen collected by Tom Morris, 21 November 2011 from nearby Miller’s Crossing or Miller’s Ferry Spring. The holotype is deposited in the National Museum of Natural History, Smithsonian Institution ( NMNH 1222549); paratypes are in the research collection of J.R. Holsinger at Old Dominion University.

Diagnosis. Relatively large and rare species of troglomorphic facies distinguished by large and robust propodi of gnathopods 1 and 2, relatively long antennae, pereopods, and uropods 1 and 2 and long, narrow, tapered telson bearing 6 relatively robust, terminal spines and 2 tiny mid-lateral spines.

Description. Antenna 1 ( Fig. 2 View FIGURE 2 a): approximately 60% length of body, approximately 65–70% longer than antenna 2; primary flagellum with 29 articles, 1st 10 or 11 bearing aesthetascs; accessory flagellum with 2 articles slightly shorter in length than first 2 flagellar articles. Antenna 2 ( Fig. 2 View FIGURE 2 b): flagellum with 7 articles. Mandibles ( Figs. 2 View FIGURE 2 c and 3d) generally similar but differing slightly in a number of important structural details as shown; molars differing slightly but both with heavily serrate cutting margins and 1 seta each; lower lip (inner margins vestigial ( Fig. 2 View FIGURE 2 e); maxilla 1 ( Fig. 2 View FIGURE 2 f); maxilla 2 ( Fig. 2 View FIGURE 2 g); maxilliped ( Fig. 2 View FIGURE 2 h) inner plate with 6 apical plumose setae, outer plate with 6 apical spines (all notched), palp with 7 apical spines. All mouthparts drawn to same scale; antennae to smaller scale.

Gnathopod 1( Fig. 3 View FIGURE 3 a): propodus slightly larger than propodus of gnathopod 2, palm nearly straight and relatively smooth, much longer than posterior margin, bearing a complex, uneven double row of approximately 40 spines of highly variable length; dactyl nail much shorter than dactyl; posterior margin proportionately very short and lacking spines; coxa subovate, bearing few short setae. Gnathopod 2 ( Fig. 3 View FIGURE 3 b): palm weakly convex, more than 2× length of posterior margin, bearing double row of approximately 40 spines of unequal length, in addition to 4 much longer spines near defining angle; posterior margin much shorter than palm, bearing several sets of setae of unequal length. Coxa subovate but larger than that of gnathopod 1, with 5 marginal setae of unequal length.

Pereopods 3 and 4 ( Figs. 4 View FIGURE 4 a, 4b): subequal, shorter than pereopod 5, coxa of 3 smaller than that of 4 and bearing fewer marginal setae. Pereopods 5 and 6 ( Figs. 4 View FIGURE 4 c, d) subequal in length and overall structure. Pereopod 7 ( Fig. 4 View FIGURE 4 e) slightly shorter than pereopods 5 and 6, with shorter coxal plate, and lacking sternal gill and brood plate. Dactyls of pereopods relatively long, approximately 1/3 length of corresponding propodi. Stalked coxal gills present on pereopods 3 and 4; simple (unstalked) on pereopods 5 & 6; absent from 7.

Pleonal plates ( Fig. 5 View FIGURE 5 a) generally similar: ventral margins weakly convex, each with 1 to 4 tiny marginal spines; posterior margins nearly straight, each with 1 tiny seta near corner. Pleopods biramous, normal for genus, not shown. Urosomites not fused. Uropod 1( Fig. 5 View FIGURE 5 b2): peduncle robust, subequal in length to rami, with 5 spines on upper margin; rami sub equal in length, outer with 4 upper marginal spines and 5 shorter terminal spines. Uropod 2 ( Fig. 5 View FIGURE 5 b1) approximately 75% length of uropod 1, peduncle with 3 spines on upper margin; rami sub equal in length, each bearing 4 upper marginal spines and 2 or 3 terminal spines. Uropod 3( Fig. 5 View FIGURE 5 c) significantly shorter than uropod 1, bearing 3 short apical spines. Telson ( Fig. 5 View FIGURE 5 d) relatively long, tapering, more than 2× longer than wide, apex bearing 6 relatively small spines.

Type locality. Skipper Spring, Washington County, Florida ( Fig. 1 View FIGURE 1 ).

Etymology. The epithet floridanus is in recognition of its occurrence in the state of Florida. Distribution and Ecology. This species is known to date only from the Skipper Spring, and nearby Miller’s Crossing or Miller’s Ferry Spring in Washington County, Florida, USA.

NMNH

Smithsonian Institution, National Museum of Natural History

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