Leocratides ehlersi ( Horst, 1921 )

Salazar-Vallejo, Sergio I., 2020, Revision of Leocrates Kinberg, 1866 and Leocratides Ehlers, 1908 (Annelida, Errantia, Hesionidae), Zootaxa 4739 (1), pp. 1-114 : 74-76

publication ID

https://doi.org/ 10.11646/zootaxa.4739.1.1

publication LSID

lsid:zoobank.org:pub:544B9C82-BF33-4EA1-9411-E1A307137466

DOI

https://doi.org/10.5281/zenodo.3680207

persistent identifier

https://treatment.plazi.org/id/2D1987E4-FFAA-7367-FF23-F9C2F5EA65E1

treatment provided by

Plazi

scientific name

Leocratides ehlersi ( Horst, 1921 )
status

 

Leocratides ehlersi ( Horst, 1921) View in CoL reinstated

Figure 42 View FIGURE 42

Leocrates ehlersi Horst, 1921: 82 View in CoL ; Hessle 1925: 15, Fig. 3 View FIGURE 3 a–c, Pl. 1, Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 , Pl. 2, Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 3 .

Leocrates (Leocratides) ehlersi: Horst 1924: 194–195 View in CoL , Pl. 36, Figs 10–12 View FIGURE 10 View FIGURE 11 View FIGURE 12 (n. comb.); Augener 1926: 452.

Leocratides ehlersi: Fauvel 1932: 62, 1953b: 107–108 View in CoL , Fig. 51 View FIGURE 51 a–c.

Leocratides filamentosus: Pettibone 1970: 230–233 View in CoL , Figs 27–29 View FIGURE 27 View FIGURE 28 View FIGURE 29 (partim, figure 29, non Ehlers, 1901).

Type material. Indonesia. Fifteen syntypes in two museums: 13 syntypes ( ZMA V.Pol. 533), and two others ( USNM 37646 View Materials ), Lesser Sunda Islands, Sumbawa, North coast, Saleh Bay , R / V Siboga Exped., Sta. 312 (08°19’ S, 117°41’ E), 274 m, trawl, muddy bottom/sand, 14 Feb. 1900 GoogleMaps .

Additional material. Philippines. Two specimens ( ECOSUR 3078 View Materials , Musorstom 3-143), Sta. 143 (11°28’ N, 124°12’ E), 205–214 m (190–198 m in label), 1 Jun. 1985 [15.5–16.0 mm long, 2.5 mm wide] GoogleMaps . New Caledonia. One specimen (MNHN Musorstom SMIB 3-17), Campagne SMIB 3, R/V Vauban, Sta. 17 (23°40.60’ S, 167°59.40’ E), 238 m, 23 May 1987 [This looks like a different species. It has entire, smooth dorsolateral tubercles; median antenna more than twice longer than prostomium, lateral antennae about three times longer than prostomium. Nuchal organs lobes markedly projected beyond lateral prostomial margin. Parapodia are in poor shape and better specimens are needed for its formal description, provided they confirm a different species is involved].

Description. Largest syntype (ZMA V.Pol. 533) complete, slightly damaged, bent laterally. Body blunt anteriorly, wider anteriorly, tapered posteriorly ( Fig. 42A View FIGURE 42 ); 28 mm long, 3.5 mm wide, 16 chaetigers; right parapodia of chaetigers 8 and 15 removed for observing parapodial features. Tentacular and dorsal cirri without tips. Dorsal surface pale, venter with a wide longitudinal brownish band along body, triangular in tentacular belt. Becoming roughtly X-shaped along chaetigers 5–6, less defined in middle and posterior chaetigers ( Fig. 42B View FIGURE 42 ).

Prostomium slightly wider than long, slightly wider anteriorly, lateral margins curved, convergent ( Fig. 42C View FIGURE 42 ). Lateral antennae with ceratophores distinct, as long as prostomium, slightly longer than palps; palpophores twice longer than palpostyles; median antenna thinner and slightly shorter than lateral antennae, markedly surpassing anterior prostomial margin, inserted centrally among eyes.

Eyes barely pigmented, round, anterior ones twice larger and more separated than posterior ones; in lateral view, anterior and posterior eyes separated from each other.

Nuchal organs lobes completely exposed, divergent oval ridges, markedly separated middorsaly; lateral ciliated bands not visible dorsally. Tentacular cirri without tips, longest ones reach chaetiger 7. Lateral cushions projected, swollen, bipartite along body, longitudinal striae not visible.

Pharynx partially exposed ( Fig. 42D, E View FIGURE 42 ). Upper jaw double, missing in largest syntype, present in other ones; crescent shaped, lower jaw single, tapered. Anterior margin smooth, without papillae. Lateral vesicles round, low, not fully projected.

Peristomial dorsolateral tubercles projected, narrower than prostomium, each with 2 low, round, wider than long lobes. Ventral ridge with 7–8 regular constrictions, barely projected, markedly wider than long.

Dorsal cirri mostly broken or without tips, longest one longer than body width including parapodia. Neuracicular lobes tapered, three times longer than wide, tips blunt, directed distally or slightly upwards ( Fig. 42F View FIGURE 42 ). Neurochaetae about 18 per bundle, blades most missing, apparently decreasing in size ventrally, bidentate, without guards, blades 3–4 times longer than wide ( Fig. 42F View FIGURE 42 , insets).

Posterior region tapered. Prepygidial segment short, with dorsal cirri 3–4 times longer than ventral ones. Pygidium with anus terminal, anal cirri broken, reaching chaetiger 16.

Oocytes visible in posterior chaetigers, each about 120 µm. Gonad fragments in middle chaetigers contain only spermatids.

Variation. Syntypes 18–28 mm long, 3.0– 3.5 mm wide. Dorsolateral peristomial tubercles always narrower than prostomium, with up to three lobes each, but sometimes they barely defined by shallow furrows, whereas the ventral ridge can have up to 9 round lobes, each as long as wide. Eyes are round, most barely pigmented, or colorless. Median antenna, or its scar, always inserted centrally between eyes. The lateral pharynx vesicles rarely fully projected, when it occurs, they are globose, blunt. Midventral pigmented longitudinal bands is constant (a badly damaged specimen has a double, longitudinal thin band, leaving a paler middle area). Most neurochaetal blades missing, probably they are delicate, or easily torn off when specimens are removed from the hexactinellid sponge they live in.

Remarks. Leocratides ehlersi ( Horst, 1921) reinstated, has been regarded as a junior synonym of L. filamentosus Ehlers, 1908 by Augener (1926: 452) and Pettibone (1970: 230), but others have regarded it as a distinct species ( Fauvel 1932: 62, 1953b: 107; Pleijel 1998: 112, 160). These two species differ, as indicated in the key above, and consequently it is formaly reinstated. In fact, L. ehlersi resembles L. kimuraorum Jimi, Tanaka & Kajihara, 2017 from Japan, by having peristomial dorsolateral ridges with a few to none lobes, and ventral pigmentation. However, these species differ, in the type of neuracicular lobes and pigmentation patterns. In L. ehlersi neuracicular lobes are markedly longer than wide, triangular, non-mucronate, and there is a ventral continuous brownish band, whereas in L. kimuraorum the neuracicular lobes are as long as wide, mucronate, and ventral pigmentation is spotty, never continuous.

There are other records for the Andaman Sea by Fauvel (1932: 62, 1953b: 107–108, Fig. 51 View FIGURE 51 a–c), and for the Red Sea by Fishelson & Rullier (1969: 59–60). However, because their specimens were not available, they cannot be confirmed.

Distribution. Originally described as living in an hexactinellid sponge, Aphrocallistes sp., in 274 m deep, off Sumbawa, Indonesia.

ZMA

Universiteit van Amsterdam, Zoologisch Museum

Kingdom

Animalia

Phylum

Annelida

Class

Polychaeta

Order

Phyllodocida

Family

Hesionidae

Genus

Leocratides

Loc

Leocratides ehlersi ( Horst, 1921 )

Salazar-Vallejo, Sergio I. 2020
2020
Loc

Leocratides filamentosus:

Pettibone, M. H. 1970: 233
1970
Loc

Leocratides ehlersi:

Fauvel, P. 1953: 107
Fauvel, P. 1932: 62
1932
Loc

Leocrates (Leocratides) ehlersi:

Augener, H. 1926: 452
Horst, R. 1924: 195
1924
Loc

Leocrates ehlersi

Hessle, C. 1925: 15
Horst, R. 1921: 82
1921
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