Pelogenia brevipalpata, Cruz-Gómez, 2022

Cruz-Gómez, Christopher, 2022, Pelogeniinae Chamberlin, 1919 (Annelida, Sigalionidae) from the Grand Caribbean Region, European Journal of Taxonomy 807, pp. 1-59 : 32-35

Pelogenia brevipalpata sp. nov.

urn:lsid:zoobank.org:act:EFBE7668-24D6-4DA3-838D-06AE49

Figs 13–14

Diagnosis

A species of Pelogenia with short palps, barely reaching segments 3–4; middorsal lobe of segment II absent; neurochaetae from segment II with smooth basal surface; neurochaetae from posterior segment with blades long; papillate medial processes in posterior elytra.

Etymology

The specific name of the species brevipalpata is a combination of the Latin singular adjective ‘ brevis (-es)’, meaning ‘short’, and the noun ‘ palpus (-i)’, adding the suffix ‘ -ata ’, meaning ‘having tentacles or tentacled’. The name indicates that the palps are very short, and it is feminine to match the generic gender ( ICZN 1999, Art. 31.2).

Material examined

Holotype MEXICO • complete spec.; Quintana Roo, Banco Chinchorro , C. Norte ; approximately 18°44′07″ N, 87°20′11″ W; May 1998; ECOSUR 289 .

Paratype MEXICO • 1 incomplete spec., 52 segments, 0.9 cm long, 0.6 cm to segment 30, 0.6 cm wide; Quintana Roo, Punta Herradura ; 18°32′23″ N, 87°44′32″ W; depth 2 m; 28 October 1997; S.I. Salazar-Vallejo and L.F. Carrera-Parra leg; dead coral; ECOSUR 290 .

Description (holotype)

BODY. Pale orange, long, broad ( Fig. 13A ); 120 segments, 3.2 cm long, 0.8 cm to segment 30, 3.2 cm wide. Middorsal line covered with white foreign particles attached to adhesive papillae ( Fig. 13B ), and only one damaged elytron remaining attached to the body; paratype with no remaining elytra. Venter covered only with large globular papillae ( Fig. 13C ).

PROSTOMIUM. Oval, wider than long. Two pairs of eyes, anterior eyes larger, inserted anteriorly. Lateral antennae short, slender; ceratophores short, styles as long as ceratophores, dorsally fused with tentacular segment, partially covered by median antennal ceratophore ( Fig. 13D–E ). Median antenna with bulbous ceratophore, slightly longer than prostomium, with a longitudinal ridge; style very slender, short, as

long as prostomium ( Fig. 13D ). Middorsal lobe of segment II absent. First segment directed anteriorly, fused with tentacular segment; biramous, chaetae simple verticillate. Dorsal tentacular cirrus longer than neuropodia including chaetae, ventral tentacular cirrus as long as dorsal tentacular cirrus; palps short reaching segment three, with inner palpal sheaths, left palp missing ( Fig. 13C ).

ELYTRA. Only one posterior elytron was found. Damaged posterior right elytron oval, with three posterior processes, anteriorly notched ( Fig. 14A ); surface with flat papillae, marginal papillae short and long dendritic ( Fig. 14G ).

RIGHT PARAPODIUM FROM SEGMENT II ( Fig. 13G ). Notopodia conical, smooth (non-papillate), short, as long as neuropodia; notopodial flange smooth (non-papillate), small. With up to 100 simple verticillate notochaetae, tips hooked, shortest ones ⅓ as long as notopodia; longest ones 3 × as long ( Fig. 13H ).

Neuropodia truncated, smooth (non-papillate), with a truncated lobe ( Fig. 13G ). Neurochaetae falcigers and spinigers; all blades entire with hooked tips, but in units C and D, tapered: unit A, six falcigers with handles slender, covered by transverse rows of spines, blades long, 10 × as long as wide ( Fig. 13I ); unit B, four neurochaetae with handles thick, covered by transverse rows of spines, blades lost ( Fig. 13J ); units C and D undifferentiated, one spiniger with handle slender, covered by transverse rows of spines, blade long, 13× as long as wide ( Fig. 13K ).

RIGHT PARAPODIUM FROM SEGMENT III ( Fig. 13L ). Dorsal cirrophore as long as cirrostyle ( Fig. 13F ). Notopodia conical, smooth (non-papillate), short, slightly shorter than neuropodia; notopodial flange rounded. With up to 30 simple verticillate notochaetae, tips hooked, shortest ones twice as long as notopodia, longest ones 3 × as long ( Fig. 13M ). Neuropodia conical, papillate, short ( Fig. 13L ). Neurochaetae only falcigers; blades entire, slightly falcate: unit A, one neurochaeta with handle slender with 9 transverse rows of spines, blade lost ( Fig. 13N ); unit B, four neurochaetae with handles thick with 7–9 transverse rows of spines, blade lost ( Fig. 13O ); unit C, three falcigers with handles slender with 8–12 transverse rows of spines, blades long, 10× as long as wide ( Fig. 13P ); unit D, four falcigers with handles slender with 13–15 transverse row of spines, blades long, 9–10 × as long as wide ( Fig. 13Q ).

RIGHT PARAPODIUM FROM SEGMENT 28 (MIDDLE SEGMENT) ( Figs 13R , 14B ). Notopodia conical, short, smooth (non-papillate), half as long as neuropodia. With up to 80 simple verticillate notochaetae, tips hooked, shortest ones twice as long as notopodia, longest ones 3× as long ( Figs 13S , 14C ). Neuropodia conical, papillate. Neurochaetae only falcigers; all blades entire, falcate: unit A, three falcigers, handles thick with transverse rows of denticles, blades medium-sized, 6 × as long as wide ( Figs 13T , 14D ); unit B, three falcigers with handles thick with barely perceptible transverse rows of denticles, blades medium-sized, 5× as long as wide ( Fig. 13U ); unit C, two falcigers with handles slender, smooth, blades medium-sized, 6–7 × as long as wide ( Figs 13V , 14E ); subunit 1, four falcigers with handles thick with barely seen transverse rows of denticles, blades short, 3–4× as long as wide ( Figs 13W , 14E ); unit D, four falcigers with handles slender, smooth, blades long, 14–16× as long as wide ( Figs 13X , 14F ).

PYGIDIUM. Rounded with two anal cirri ( Fig. 14H ).

Remarks

Pelogenia brevipalpata sp. nov. is grouped with other species that have posterior elytra with papillate medial processes and some posterior processes, such as P. arenosa delle Chiaje, 1830, P. fimbriata ( Hartman, 1939) , and P. kinbergi ( Hansen, 1882) . However, P. brevipalpata sp. nov. differs from these three species in having short palps barely reaching segment 4 and lacking a middorsal lobe on segment II. Well-preserved specimens might enhance the morphological details of the species, regarding elytra and neurochaetae from anterior segments.

Distribution

Caribbean Sea. Quintana Roo, Mexico.

Figures

Fig. 13. Pelogenia brevipalpata sp. nov., holotype (ECOSUR 289). A. Complete worm, dorsal view. B. Anterior end, dorsal view (insert: dorsal papillae). C. Anterior end, ventral view, arrowhead indicates palp (insert: ventral papillae). D. Median antenna. E. Lateral antenna. F. Right dorsal cirrus from segment III. G. Right parapodium from segment II. H. Notochaeta from same. I. Unit A. J. Unit B. K. Units C and D. L. Right parapodium from segment III. M. Notochaeta from same. N. Unit A. O. Unit B. P. Unit C. Q. Unit D. R. Right parapodium from segment 28. S. Notochaeta from same. T. Unit A. U. Unit B. V. Unit C. W. Subunit 1. X. Unit D. Scale bars: A = 5 mm; B–C = 1 mm; D–G, L, R = 500 μm; H, M, S = 40 μm; I–K, N–Q, T–X = 50 μm.

Fig. 14. Pelogenia brevipalpata sp. nov. B–F. SEM micrographs. Holotype (ECOSUR 289).A. Posterior damaged elytron. B. Right parapodium from segment 28. C. Notochaetae from same. D. Unit A.E. Units C and subunit 1. F. Unit D. G. Close-up from A, median margin. H. Pygidium. Abbreviations: a = anterior; p = posterior. Scale bars: A, H = 500 μm; B, G = 100 μm; C = 10 μm; D, F = 20 μm; E = 50 μm.