Laubieriellus Maciolek, 1981b

Peixoto, Antônio João Malafaia & Paiva, Paulo Cesar De, 2019, New Prionospio and Laubieriellus (Annelida: Spionidae) species from Southeastern Brazil, Zootaxa 4577 (3), pp. 529-547 : 539-540

Genus Laubieriellus Maciolek, 1981b

Type-species: Laubieriellus grasslei Maciolek, 1981b

Diagnosis (emended from Erickson & Wilson, 2018): Prostomium anteriorly rounded, or with slight medial incision, extended posteriorly as a caruncle, occipital tentacle absent. Peristomium distinct from chaetiger 1, partly fused to prostomium. Four pairs of branchiae from chaetiger 2; branchiae elongate, cylindrical, smooth and distinct from notopodial lamellae. Neuropodial lamellae connected by ventral crests from chaetiger 2, rarely 1. Postbranchial notopodial lamellae connected in dorsal crests. Anterior chaetae all capillaries, multidentate hooded hooks present in posterior neuropodia. Notopodial hooks absent. Pygidium with two short ventrolateral lobes or cirri and one dorsomedial cirrus, or three subequal lobes or an undifferentiated ring.

Remarks: Maciolek (1981b) described Laubieriellus based on deep-sea specimens found on the Galápagos Rift and also placed Prionospio salzi Laubier, 1970 in Laubieriellus . Laubier (1970) considered his specimens as late-stage larvae, despite an adult morphology, as noted by Maciolek (1981b). The reexamination of the holotype (USNM 42621) also revealed the presence of oocytes from chaetiger 9–10.

Blake et al. (2017) considered Laubieriellus as part of the Prionospio -complex, as although morphologically similar to Prionospio , Laubieriellus species lack notopodial hooks and present ventral crests on several anterior chaetigers. The ventral crest, however, is not exclusive to Laubieriellus and has been observed in Prionospio rugosa Sigvaldadóttir, 1997 and Prionospio cristaventralis, Delgado-Blas et al. 2018 . The genus diagnosis was emended to include a ventral crest on chaetiger 1, as observed in Laubieriellus grasslei ( Fig. 10 ).

The notch on the ventral crests, a character generally neglected, is present in Laubieriellus grasslei ( Maciolek 1981b: Fig. 4A ), L. cacatua Erickson & Wilson, 2018 , L. decapitata sp. nov. ( Fig. 11B ; 12C ) and L. salzi ( Laubier 1970; Dagli 2013: Fig. 3A ), as indicated in Laubier’s (1970) description: “Enfin, en avant du neuropode une crête fine se prolonge ventralement presque jusqu'h la ligne médioventrale.” (Finally, in front of the neuropodium, a fine crest extends ventrally almost to the medioventral line). This notch can be shallow and incomplete, as seen in L. cacatua and L. decapitata sp. nov., or a complete notch, as in L. salzi and L. grasslei ( Fig 10 B–C).

Figures

FIGURE 3. SEM of Prionospio solisi sp. nov. A. Anterior chaetigers, dorso-lateral view. B. Mid-body neuropodium, lateral view. C. Posterior neuropodium, dorso-lateral view. D. Pygidium, dorso-lateral view. Abbreviations: br, branchia; hh, hooded hook; py, pygidium, sa, sabre chaeta.

FIGURE 4. SEM of Prionospio solisi sp. nov., dorsal view. A. Anterior chaetigers and mid-body. B. Anterior chaetigers. Abbreviations: br, branchia; bs, branchial scars; nol, notopodial lamella; pe, peristomium; pr, prostomium.

FIGURE 10. SEM of Laubieriellus grasslei (USNM 65918, paratypes). A. Anterior and median chaetigers, dorsal view. B. Anterior and median chaetigers, ventral view. C. Close-up of the ventral crests, ventral view. Abbreviations: br, branchia; cha1, chaetiger 1; cn, complete notch; dc, dorsal crests; pe, peristomium; pr, prostomium; vc, ventral crests.

FIGURE 11. Laubieriellus decapitata sp. nov. (MNRJP 1831, paratypes). A. Anterior chaetigers, dorsal view. B. Anterior chaetigers, ventral view. Abbreviations: dc, dorsal crest; pe, peristomium; pr, prostomium; vc, ventral crest.

FIGURE 12. SEM of Laubieriellus decapitata sp. nov. A. Anterior chaetigers, dorsal view. B. Anterior chaetigers, dorsolateral view. C. Anterior chaetigers, ventral view. D. Hooks (hoods removed), lateral view. Abbreviations: br, branchia; dc, dorsal crest; pr, prostomium; vc, ventral crest.