Godzillius louriei Ballou, Bracken-Grissom & Olesen, 2021

Ballou, Lauren, Iliffe, Thomas M., Kakuk, Brian, Gonzalez, Brett C., Osborn, Karen J., Worsaae, Katrine, Meland, Kenneth, Broad, Kenneth, Bracken-Grissom, Heather & Olesen, Jørgen, 2021, Monsters in the dark: systematics and biogeography of the stygobitic genus Godzillius (Crustacea: Remipedia) from the Lucayan Archipelago, European Journal of Taxonomy 751 (1), pp. 115-139 : 121-129

Godzillius louriei Ballou, Bracken-Grissom & Olesen sp. nov.

urn:lsid:zoobank.org:act:F0D0FD57-4ACF-4BC3-B8D2-CBCF00E16026

Figs 3–8

Diagnosis

25 mm in length with 29 trunk segments. Cephalic shield subtrapezoidal. Pleurotergite lateral margins pointed posteriorly. Sternal bars isomorphic. A1 bifurcated, dorsal branch with 11 articles. Right and left md gnathal edges crescentiform, asymmetrical; left lacinia mobilis with 5 denticulae. Mx1 with 7 segments; segment 1 with 10 large and 3 small spines; segment 4 endite digitiform, anterior margin lined with 10 conical denticulae. Mx2 with 6 segments; distal segment unguiform, bearing seven denticulae. Mxp with 9 segments; terminal claw with conical, laminate spines. Caudal rami short and distally covered with plumose setae.

Etymology

Named for Robert Lourie whose financial support of the Bahamas Caves Research Foundation contributes to furthering cave and blue hole related research in the Bahamas. The taxonomic description and underlying molecular justification for Godzillius louriei sp. nov. was prepared by LB, HBG, and JO, who are thus responsible for making the specific name louriei available.

Material examined

Holotype BAHAMAS • holotype; North Andros Island , Conch Sound Blue Hole , The Collapse Room ; 25°07′ N, 78°00′ W; depth 30–32 m, approximately 1600 m horizontal distance from single cave entrance; 4 Sep. 2017; B. Kakuk leg.; specimen dissected and distributed on four light microscopy slides, six SEM stubs and one alcohol voucher; GenBank: MW760699 , MW768712 ; NHMD 669698 .

Description

CEPHALON ( Fig. 3 ). Cephalic shield subtrapezoidal, posterior margins wider than anterior. Posteriolateral margins rounded; sutures absent. Anterior margin folds ventrally, covering a1 aesthetascs and bifurcated frontal filaments.

BODY ( Fig. 3 ). Body length 25 mm; 29 trunk segments. Pleurotergite lateral margins pointed posteriorly. Sternal bars isomorphic. Trunk limbs bifurcated with endopods and exopods consisting of three and four segments respectively. Trunk limbs 1 and 18–29 reduced in size ( Figs 3–4 ). Trunk limb 14 protopod with large lobate protrusion and ventrally with slender genital flap ( Fig. 3F ).

ANTENNA 1 ( Fig. 4A ). Biramous, located posterior to frontal filaments. Peduncle with two articles; proximal article bearing numerous aesthetascs. Distal peduncle article bifurcated, acts as base of dorsal and ventral rami. Dorsal ramus (i.e., dorsal branch) with 11 articles; girth decreasing distally through articles. Article 1 with single anteriodistal setal cluster; article 2 with one medial seta, one distal cluster; article 3 with two medial setae; article 4 with two medial setae, one distal seta, fine marginal setae; article 5 with one medial seta, one distal cluster; article 6 with three medial setae, one distal seta; article 7 possessing two to three medial setae, one distal seta; article 8 bearing one fine medial seta; articles 9 and 10 lacking setae; article 11 with terminal tuft of setae. Ventral ramus (i.e., ventral branch) with ambiguous articulation, treated as three articles ( Fig. 4A ). Proximal article shorter than article 2, no setae, partly fused with peduncle. Article 2 length ~2× that of proximal article. Article 3 length ~3× that of article 2, with one filiform medial seta and a distal setal tuft.

ANTENNA 2 ( Fig. 4B ). Protopod with two articles (i.e., coxa and basis). Basis with exopod unarticulate and endopod of three articles. Exopod ovoid, lateral margin with ~50 long, plumose setae. Endopod proximal article distomedial margin bearing two long setae. Article 2 median margin with 10–20 long setae; lateral margin with 3–4 short setae. Article 3 entire margin with 55–65 setae.

MANDIBLE ( Fig. 5 ). Gnathal edge comprised of lacinia mobilis, incisor and molar process. Molar processes crescentiform, with slight invagination along midline. Molar process wider ventrally than dorsally, covered in setae. Left and right md asymmetrical; right incisor with three slightly serrated denticulae extending medially towards atrium oris; left with three distinctly serrated denticulae and small fourth tooth on posterior margin. Right lacinia mobilis with three slightly serrated denticulae; left with five smooth, uneven denticulae.

MAXILLA 1 ( Fig. 6 ). Comprised of seven segments, posterior to a2. Segment 1 with medially-extending endite bearing ten conical spines and three small spines ( Fig. 6D–E ). Segment 2 with dorso-ventrally flattened, broad, spatulate endite; oblong distal edge of endite with 4–5 short conical spines and 25–30 moderate to long simple setae. Segment 3 with no setae nor endites. Segment 4 robust with single digitiform endite extending medially; medial anterior margin bearing ten conical denticles, decreasing in size distally, and endite disto-medial edge with ~19–20 long, simple setae ( Fig. 6F ). Segment 4 anteromedial face with setal cluster of 11 moderate, simple setae. Segment 5 robust, with proximal cluster of simple setae. Segment 6 narrow, ventral margin with a long, simple setal cluster (at least 23 setae); anterior and posterior faces with two long, simple clusters. Segment 7 with long, simple setal cluster

underneath elongate, robust, talon-like claw. Claw distally curved towards atrium oris; duct opening at distal tip.

MAXILLA 2 ( Fig. 7 ). Comprised of six segments, posterior to mx1. Segment 1 with three digitiform endites (a–c on Fig. 7K–L ) angled antero-medially; each endite distal margin with one conical spine, pore cluster and a variable number of short, simple setae (endite a, 5 setae; endite b, 14; endite c, 15). Each endite anterior margin with long, simple setae (endite a, 1 seta; endite b, 2; endite c, 2). Segment 1 posterior maxillary gland comprised of large tubular conduit opening toward cephalic shield ( Fig. 7J ). Segment 2 with one conical endite extending postero-medially; bearing distal cluster of short, simple setae ( Fig. 7G–I ). Segment 3 (lacertus) somewhat triangular, longer than segments 1 and 2 combined. Lacertus ventral margin extending beyond dorsal margin; with ~four rows of moderate-to-long, vertically striated setae. Brachium (segments 4–6) extending length of lacertus; terminal claw spines extend beyond lacertus. Segment 4 extending ~ 4 / 5 length of brachium; fine setae throughout segment, with 1–3 short, simple setae at ventral distal end. Segment 5 1 / 5 length of brachium; distal margins with four short, simple setal clusters (5–6 setae in each). Segment 6 with distal arrangement of seven conical spines decreasing in length distally; curved downward over setal pad in a grappling hook arrangement (terminal claw complex) ( Fig. 7D–F ). Setal pad with long, simple setae; proximal edge conical, lacking setae, directed towards lacertus.

MAXILLIPED ( Fig. 8 ). Comprised of nine distinct segments, with flexion point between segments 5 and 6. Segment 1 with one medial setal cluster of five small, vertically striated setae. Segment 2 anterior face proximal medial margin with eight vertically striated setae; posterior face medial margin with six short, vertically striated setae. Segment 3 triangular along posterior face; proximal margin three times wider than distal margin. Distal margin of segments 3 and 4 align, reaching proximal margin of segment 5 (lacertus). Segment 3 anterior face rectangular and narrower than segment 2; proximal medial margin bearing four small setae (2 grooved, 1 simple, 1 conical). Segment 4 exhibiting different shapes along anterior and posterior faces. Segment 4 posterior face triangular, with proximal margin narrower than distal margin; proximal margin with one vertically-striated seta and 2–3 simple setae. Segment 4 anterior face rectangular, small suture along its length; with two small, vertically striated setae. Segment 5 similar in shape to lacertus of mx2; width decreasing proximally to distally. Lacertus with rows of vertically striated setae along ventral margin ( Fig. 8D ). Segments 6–9 (brachium) extending beyond length of lacertus. Brachium with short setae along surface, subsiding at terminal claw complex. Segment 6 nearing length of lacertus; distal margin with setal cluster of three simple setae. Segment 7 ~ 1 / 8 length of segment 6; extends beyond lacertus with distal cluster of three simple setae. Segment 8 longer than segment 7, with one setal cluster (5 simple setae, moderate length) above terminal claw, one posterior cluster (5 simple setae, moderate length) and two clusters (several simple setae, moderate length) oriented towards lacertus. Segment 9 with terminal claw complex ( Fig. 8E–F ); at least seven curved spines extending over setal pad (difficult to give exact number due to position of appendage). Six most proximal spines conical, robust; distal spine(s) small, laminate. Setal pad covered by terminal claw, protrudes downward, with long simple setae.

TELSON, CAUDAL RAMI ( Figs 3 , 8 ). Telson subrectangular, slightly longer than wide; ventral surface medial axis with deep invagination. Caudal rami short, extending distally past edge of telson; surface bearing short, scattered, simple setae. Each ramus distal margin with single cluster of ~10 long, plumose setae.

Remarks

Species of Godzillius can be distinguished by several morphological characters, most notably relating to the md and the three pairs of prehensile/raptorial post-mandibular mouthparts ( Figs 9–10 , Table 2 ). On the left md, the lacinia mobilis of both G. louriei sp. nov. and G. fuchsi have five denticulae, whereas G. robustus has six. One of the most striking distinctions between species of Godzillius is the number of conical denticles on the mx1 endite segment 4 anteriodistal margin ( Fig. 9B, F, J ). While G. fuchsi and G. robustus have been observed or described as having between 6 and 8 denticles along its margin, G. louriei sp. nov. has 10. Furthermore, the mx1 endite first segment has a unique spination, with 10 large spines and 3 small ( Fig. 9D ), contrasting with those of G. robustus (11 large, 4 small) and G. fuchsi (10 large, 2 small).

The terminal claw of mx 2 in G. robustus is reported to have 10 free spines, whereas that of G. fuchsi and G. louriei sp. nov. have 7 ( Fig. 9O, R, U ). The mxp terminal claw in G. fuchsi has an elongate protrusion of the setal pad that is not covered by its spines ( Fig. 10F ); in contrast, the spines of G. louriei sp. nov. and G. robustus cover the setal pad ( Fig. 10B, D ). The mxp terminal claw of G. robustus has been described as a “grappling hook” with ten spines wrapping around a setal pad ( Schram et al. 1986). Godzillius louriei sp. nov. has a similar arrangement, with at least 7 spines in the grappling hook arrangement ( Fig. 10B ). Godzillius fuchsi differs from the aforementioned species, having shorter, denticle-like spines with narrow spaces between them and not covering a distinctly protruding setal pad ( Fig. 10F ). We found the mxp of all three species to be composed of 9 segments ( Fig. 10 ), modifying the previous descriptions of G. robustus and G. fuchsi , where fewer proximal segments were identified. It should be noted that this number of mxp segments coincides with what is reported for all other remipede species ( Koenemann & Iliffe 2014).

Figures

Fig. 3. Godzillius louriei sp. nov., holotype (NHMD 669698), light microscopy.A. Entire animal, ventral view. B. Entire animal, dorsal view. C. Cephalon, ventral view. D. Cephalon, dorsal view. E. Frontal filament, left side. F. Sternal bars and trunk segments (Ts), ventral view. G. Telson, lateral view.

Fig. 4. Godzillius louriei sp. nov., holotype (NHMD 669698), light microscopy. A. Antenna 1 (a1), dorsal view. B. Antenna 2 (a2), dorsal view. C. Trunk limb 1. D. Trunk limb 2. E. Trunk limb 7. F. Trunk limb 28. G. Trunk limb 29. Small numbers represent segments of the dorsal and ventral branches of a1 and the exopod of a2.

Fig. 5. Godzillius louriei sp. nov., holotype (NHMD 669698), scanning electron microscopy. A. Left mandible (md), anterior view. B. Left md, apical view of the lacinia mobilis and incisor. C. Left md, posterior view. D. Left md, apical view of the setae within the molar process. E. Right md, posterior view; incisor unintentionally removed in dissection. F. Right md, ventral view of the gnathal edge without the incisor. G. Right md, ventral view of the incisor.

Fig. 6. Godzillius louriei sp. nov., holotype (NHMD 669698), left maxilla 1 (mx1), scanning electron microscopy. A. Anterior face of mx1. B. Posterior face of mx1. C. Apical view of mx1. D–E. Endite of segment 1, unintentionally removed during dissection. F. Conical spines along the surface of the digitiform endite on segment 4, posterior view. G. Spatulate endite of segment 2, apical view. Small numbers represent segments of mx1.

Fig. 7. Godzillius louriei sp. nov., holotype (NHMD 669698), left maxilla 2 (mx2), scanning electron microscopy. A. Anterior face of mx2; endites of segment 1 indicated as lowercase letters a–c. B. Apical view of mx2. C. Posterior face of mx2. D. Terminal claw, apical view. E. Terminal claw, posterior face. F. Terminal claw, anterior face. G. Endite of segment 2, median view. H. Endite of segment 2, posterior face. I. Hollowed conical tip of the endite of segment 2. J. Maxillary gland opening of mx2. K. Triplet endites of segment 1 (a–c) and singular endite of segment 2, posterior face.L. Triplet endites of segment 1 (a–c) and singular endite of segment 2, apical view. M. Conical spine on the third endite of segment 1, apical view. N. Conical spine on the second endite of segment 1, apical view. O. Conical spine on the first endite of segment 1, apical view. Small numbers represent segments of mx2.

Fig. 8. Godzillius louriei sp. nov., holotype (NHMD 669698), left maxilliped (mxp) scanning electron microscopy. A. Anterior face of mxp. B. Posterior face of mxp. C. Apical view of mxp. D. Vertical striations of setae along the surface of the lacertus. E. Terminal claw, anterior face. F. Terminal claw, posterior face. G. Posterior segments and telson, ventral view. H. Telson, lateral view; caudal rami separated by invagination of the telson. Small numbers represent segments of mxp.

Fig. 9. Morphological comparison of maxilla 1 (mx1) and maxilla 2 (mx2) between Godzillius louriei sp. nov. (NHMD 669698) (A–D, M–O),G. robustus Schram, Yager & Emerson, 1986 (UNSM 1524349) (E–H, P–R) and G. fuchsi Gonzalez, Singpiel & Schlagner, 2013 (NHMD 165841) (I–L, S–U), scanning electron microscopy. A. Left mx1, posterior face. B. Digitiform endite on segment 4, posterior view. C. Spatulate endite of segment 2. D. Endite of segment 1. E. Left mx1, posterior face. F. Digitiform endite on segment 4, posterior view. G. Spatulate endite of segment 2. H. Endite of segment 1. I. Right mx1, posterior face (mirrored). J. Digitiform endite on segment 4, posterior view. K. Spatulate endite of segment 2. L. Endite of segment 1. M. Left mx2, posterior face. N. Apical view of terminal claw. O. Posterior view of terminal claw. P. Left mx2, posterior face. Q. Apical view of terminal claw. R. Posterior view of terminal claw. S. Left mx2, posterior face. T. Apical view of terminal claw. U. Posterior view of terminal claw. Small numbers represent segments of mx1 and mx2.

Fig. 10. Morphological comparison of maxilliped (mxp) between Godzillius louriei sp. nov. (NHMD 669698) (A–B), G. robustus Schram, Yager & Emerson, 1986 (UNSM 1524349) (C–D) and G. fuchsi Gonzalez, Singpiel & Schlagner, 2013 (NHMD 165841) (E–F), scanning electron microscopy. A. Left mxp of G. louriei sp. nov., posterior face. B. Terminal claw, posterior face. C. Left mxp of G. robustus, posterior face. D. Terminal claw, posterior face. E. Right mxp of G. fuchsi, posterior face (mirrored). F. Terminal claw, posterior face. Small numbers represent segments of mxp.