Laonice praecirrata Hartmann-Schroder 1965
Creators: name: Delgado-Blas, Vi ́ Ctor Hugo
name: Díaz-Díaz, Oscar
name: Rozbaczylo, Nicolás
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Annelida
Polychaeta
Spionida
Spionidae
Laonice
Laonice praecirrata

description: Laonice praecirrata Hartmann-Schro ̈der, 1965
Figure 1A–R
Laonice cirrata var. praecirrata Hartmann-Schro ̈der, 1965: 207–208, figs 195–196.
Material examined: Seven specimens from the Puyuhuapi channel, Aysén region (44°45′32.21″S 72°53′40.25″W), MNHNCL ANN-15398, 30 m depth., 09-03-2014, coll. C. Carreño. Gravelly-muddy sediments.
Description. Complete specimen: 131 chaetigers, length 53 mm and width 2.3 mm. Six incomplete specimens with 59–106 chaetigers, lengths 13–26 mm and widths 1.0– 1.7 mm. Prostomium subtriangular, with the anterior margin broadly rounded (Fig. 1A, C), with a short, rounded lateral projections and fused to the peristomium by a small, slender membrane on the lateral sides (Fig. 1B). Peristomium moderately developed and is approximately half the length of the prostomium. One pair of large drop-shaped brownish eyespots on posterior region of prostomium (Fig. 1A). Occipital tentacle long, thick, erect and positioned just between the first pair of notopodial lamellae (Fig. 1B). Caruncle well developed, extending together with the nuchal organs to chaetigers 16–17 (Fig. 1D). Palps absent in all specimens examined.
Branchiae starting from chaetiger 2 (Fig. 1A), continuing up to chaetigers 32–41, all anterior branchiae fused basally to the notopodial lamellae (Fig. 1H–K), from chaetiger 24 branchiae free of notopodial lamellae; first three pairs of branchiae short, digitiform and with slender, pointed tips, slightly longer than the notopodial postchaetal lamellae (Fig. 1H), increasing in length significantly just after the fourth pair of notopodial lamellae and becoming one third as long as the notopodial postchaetal lamellae from chaetigers 6–8 (Fig. 1J, K). From chaetiger 22, the length of the longest branchiae (Fig. 1L) equal to the total width of the body, length gradually diminishing posteriorly.
Notopodial postchaetal lamellae of chaetiger 1 small, triangular, shorter than neurolamellae (Fig. 1G), increases in size noticeably from the second lamella into broad subtriangular lamellae with blunt tips (Fig. 1H), the largest lamellae on chaetigers 4–6 (Fig. 1D, I); lamellae becoming kidney-shaped from chaetigers 7–13 (Fig. 1D, J), gradually decreasing in size; from chaetiger 14 lamellae with blunt triangular tips with the ventral edges extended and rounded (Fig. 1K, L); the tips then gradually lengthening slightly to become a triangular lamella along the body (Fig. 1H–I). Notopodial prechaetal lamellae reduced on first chaetigers, thereafter lamellae moderate. Dorsal transverse crests connecting notopodial postchaetal lamellae from chaetigers 17–18 (Fig. 1F) disappearing on the last 27 chaetigers.
Neuropodial postchaetal lamellae of chaetigers 1–2 broadly rounded (Fig. 1B, C), subtriangular with blunt tips from chaetiger 3 (Fig. 1B, G), increasing gradually in size (Fig. 1C, I). Neuropodial prechaetal lamellae on first chaetigers reduced, increasing in size thereafter, and well developed from chaetiger 7 (Fig. 1C), fused with the dorsal edge of neuropodial postchaetal lamellae (Fig. 1K), gradually reducing in size until the appearance of the ventrolateral pouches. Ventrolateral pouches (Fig. 1E) starting from chaetigers 15–17 and present up to chaetiger 124. First pouch very small, emerging from dorsal part of prechaetal lamellae and posterior dorsal base of neuropodial lamellae. Pouches present irregularly, probably because they break easily, and absent posteriorly (from the last seven chaetigers).
First parapodium with capillaries arranged in two rows; notopodial lamellae from chaetigers 5–12 with five rows, first four rows with thick (coarse), granulate, bilimbate chaetae (Fig. 1M), fifth row with long, striate, bilimbate chaetae (Fig. 1N); one row of chaetae from chaetiger 23, with long, thin, striate, alimbate capillary chaetae (Fig. 1O). Neuropodial capillaries from chaetigers 3–5 arranged in three rows, the first row with very heavily granulated, alimbate capillary chaetae (Fig. 1P); the second row with lightly granulated, alimbate chaetae; the third row with very granulated, unilimbate capillary chaetae; the fourth and fifth rows with thick, granulated, and distally bilimbate chaetae with thin veils. Two rows of chaetae from chaetiger 13, one row from chaetiger 16. Neuropodial hooks from chaetigers 20–24, 8–12 hooks per fascicle; hooded hooks bidentate in lateral view, hoods striated with a small distal opening (Fig. 1Q); companion capillary chaetae present (Fig. 1R). Sabre chaetae heavily striated and granulated from chaetigers 14–15 (Fig. 1 S) numbering up to three per fascicle at the beginning, increasing to four per fascicle on the later segments. Pygidium with a pair of short ventral lobes without anal cirri (maybe lost).
Worms without pigment.
Methyl Green staining pattern. Peristomium stained profusely both dorsally and ventrally; central region of lamellae also stained. Posterior ventral margins of the first 8–10 segments stained, as well as the posterior segments dorsally (Fig. 1A–C, E).
Distribution. So far only known from the Aysén region.
Remarks. Laonice praecirrata belongs to the ‘ Laonice sarsi’ group (Sikorski & Pavlova 2016: 361). Species from this group are characterized by the following traits: the anterolateral corners of the prostomium are fused to the peristomium, generally by an inconspicuous membrane (this connecting membrane may be hidden in the groove between both); the nuchal organ is generally quite short (10 anterior chaetigers long) and varies little between specimens; and by the notopodial hooded hooks which may be present on the very posterior chaetigers. Other numerical characters are highly variable. Seven species belong to this subgenus: L. japonica (Moore, 1907); L. sarsi Soderstrom, 1920; L. antarcticae Hartman, 1953; L. dayianum Sikorski, 1997; L. sinica Sikorski & Wu, 1998; L. rossica Sikorski, 2003; and L. olgae Sikorski & Pavlova, 2016.
The morphology of the material examined agrees well with the original description of L. praecirrata (Hartmann-Schröder, 1965), although many important differences were observed. The original description identified a caruncle extending to chaetigers 14–21, with four eyes arranged into two per row on each side, posterior pairs longer; occasionally there is a pigment in front of the large eyes and to the side of the small ones; the occipital tentacle is slightly at the level of the first parapodium; branchiae are present on chaetigers 2–59, the first pairs the same length or slightly shorter than the notopodia; the anterior notopodium is lanceolate, from chaetigers 11–26 becoming a blunt extension and distally separate; hooded hooks are present from chaetigers 18–21. Subsequently, Sikorski & Pavlova (2016) provided new information such as the appearance of hooded hooks from chaetigers 17–24; the caruncle extending to chaetigers 15–21; sabre chaetae from chaetigers 11–14; ventrolateral pouches from chaetigers 9–24; the fusion of the prostomium and peristomium by an inconspicuous membrane; and the presence of transdorsal membranes.
The differences between the original descriptions given by Hartmann-Schröder (1965) and Sikorski & Pavlova (2016) and our specimens are: the presence of one pair of large drop-shaped brownish eyespots on the posterior part of the prostomium; the branchiae reach up to chaetigers 32–41 vs. chaetiger 59; ventrolateral pouches start from chaetigers 15–17 up to chaetiger 124 vs. from chaetigers 11–14. The number of hooded hooks per fascicle is 8–12 vs. 6; there are two teeth per hooded hook in the lateral view vs. three teeth, and the hoods are striated with a small distal opening; sabre chaetae appear from chaetigers 14–15, numbering up to three per fascicle at the start, before increasing to four sabre chaetae vs. sabre chaetae appearing from chaetigers 11–14, one–two per fascicle; worms without pigment. Many of these variations are possibly due to the size of the animals examined.
In addition, previous descriptions by Hartmann-Schröder (1965) and Sikorski & Pavlova (2016) do not mention several characters, such as, that all anterior branchiae are fused basally to the notopodial lamellae up to chaetiger 24 when the branchiae are free of the notopodial lamellae. They also do not describe the size and structure of the branchiae, nor the shape of the notopodial and neuropodial lamellae throughout the body, nor mention in which chaetigers the dorsal transverse crests are found. Neither do they mention the number of rows of chaetae, nor their structure, nor describe the pygidium as having a pair of short ventral lobes without anal cirri (maybe lost). Currently, the same is true for many other Laonice species whose descriptions are not standardized (some characters are mentioned in some species and in others they are omitted), which has led to much confusion.
description: Published as part of Delgado-Blas, Vi ́ Ctor Hugo, Díaz-Díaz, Oscar & Rozbaczylo, Nicolás, 2024, Laonice Malmgren, 1867 (Annelida: Spionidae) from the Aysén region in southern Chile with description of a new species, pp. 157-166 in Zootaxa 5551 (1) on pages 159-161, DOI: 10.11646/zootaxa.5551.1.7, http://zenodo.org/record/14390215