Description of Alitta yarae sp. nov. (Annelida, Nereididae): a new oligo/mesohaline species from southern Brazil

Figures & data

Figure 1. Map of the study area. Red dots mark the areas in which Alitta yarae sp. nov. occurred; blue dots mark the areas where A. succinea was collected. PEC = Paranaguá Estuarine Complex.

Figure 2. Anterior view of Alitta yarae sp. nov. (a) paratype (MNRJP 007662): anterior end, dorsal view. (b–d) Holotype (MNRJP 007659): (b) dorsal view, (c) ventral view, (d) lateral view. Arrows point to fleshy pads between areas VI and VII–VIII bearing paragnaths. Scale bars: A = 2 mm; B–D = 1 mm. cn, conical paragnath, pp, pyramidal paragnath.

Figure 3. Parapodia and posterior end of Alitta yarae sp. nov. (a–e) Holotype (pMNRJP 007659) chaetiger; (f) paratype (MNRJP 007661), posterior end, dorsal view. Scale bars: a–e = 0.5 mm; f =1 mm. AC = anal cirrus, AL = neuroacicular ligule, DC = dorsal cirrus, DL = dorsal ligule, Gl = glandular edge, IL = inferior lobe, ML = median ligule, NeA = neurociculae; NoA = notoaciculae, Prl = notopodial prechaetal lobe, Ptl = neuropodial postchaetal lobe, VC = ventral cirrus, VL = ventral ligule.

Figure 4. Detail of Alitta yarae sp. nov. chaetae from central segments (S.E.M. = scanning electron microscope; SM): (a) homogomph spiniger from notochaetae; (b) heterogomph falciger from neurochaetae; (c) heterogomph spiniger from neurochaetae. Scale bars: a = 30 µm; b, c = 50 µm.

Figure 5. Molecular-based species delineation. (a) maximum likelihood (ML) phylogeny based on cytochrome c oxidase subunit I (CO1), with information regarding the different Molecular operational taxonomic units (MOTU) delineation methods. (b) PhyloMap visualisation of Poisson tree partitions (PTP) species delimitation result. Variance explained by first and second axes: 80.35% and 16.04%, respectively. The circles represent the different haplotypes used for the analysis; the colour is relative to the result of the PTP delimitation. The complete ML phylogeny, without collapsed clades, is accessible in Suppl. file S5.

Table I. Comparison of Alitta yarae sp. nov. with the most similar congeneric species. DC = dorsal cirrus, DL = dorsal ligule.

Character	A. acutifolia	A. succinea	A. yarae sp. nov.
Area II	17–19	19–22	11–26
Area III	12–14	32–37	11–22
Area IV	20–22	22–25	10–31
Area V	5–6	1–3	0–4
Area VII-VIII	71–79	50–55	40–64
Bare space between areas VI and VII–VIII	Reduced: as wide as palpostyle	Wider: as wide as palpophore	Reduced: as wide as 1/3 palpophore
Paragnaths VII–VIII	Cones and p-bars	Conical and pyramidal	Conical and pyramidal
DC/DL anterior ch.	DC 2–3x longer than DL	DC = DL	DC 0.25x longer than DL
Dorsal cirrus: terminal position	On the last 18–22 ch.	On the last 7–14 ch.	On the last 24–27 ch.
DL: Glandular edges	Upper and lower	Lower only	Lower only
DL: Ventral surface post. ch.	Rounded	Straight	Rounded
DL width/post. ch.	DL exceeding	DL not exceeding	DL not exceeding
Blade of notopodial homogomph spinigers	Short	Long	Long
Extension of lower peristomial cirri	Exceeding beyond palp tips	As long as palps or shorter	As long as palps or shorter
Extension of lower tentacular cirri	Exceeding half of the prostomium	Reaching half of prostomium or shorter	Exceeding half of the prostomium
Antenna: shape	Thick, large, as long as or extending slightly beyond palp tips	Slender, small, barely reaching half length of palps, 1/3 prostomium length	Slender, small, not reaching half length of palps, 1/2 prostomium length
Prostomium: extension	Longer than wide	As long as wide	Wider than or as long as wide
Jaws: color	Red-amber	Yellow-amber	Yellow-amber
Paragnaths present atop a soft plate	Occasionally	Never	Never
Body length (mm)	18.3 ± 1.7	67.6 ± 14.5	42.96 ± 8.08
Brownish spots on mid dorsal surface of posterior chaetigers	Present	Absent	Absent

Table II. Species, process ID, amplified loci, habitat details, and geographical coordinates for the annelid specimens used in this work.

Species	Process ID	Amplified locus	Estuary	Sector of the estuary	Salinity (psu)	Notes – habitat	Latitude	Longitude
Alitta yarae sp. nov.	ESPBR001–21	CO1	PEC	Mesohaline	10	Mud	−25.449	−48.689
	ESPBR002–21	CO1	PEC	Oligohaline	1	Mud	−25.243	−48.415
	ESPBR003–21	CO1	PEC	Mesohaline	20	Fishing buoys	−25.435	−48.705
	ESPBR004–21	CO1	PEC	Oligohaline	3	Mud	−25.243	−48.415
	ESPBR005–21	CO1	PEC	Mesohaline	10	Mud	−25.449	−48.689
	ESPBR006–21	CO1	PEC	Mesohaline	20	Fishing buoys	−25.496	−48.498
	ESPBR012–21	CO1/16S	PEC	Mesohaline	20	Fishing buoys	−25.435	−48.705
	ESPBR164–23	CO1	PEC	Mesohaline	15	Mud	−25.446	−48.691
	ESPBR165–23	CO1	PEC	Mesohaline	15	Mud	−25.446	−48.691
	ESPBR166–23	CO1/16S/28S	PEC	Mesohaline	20	Fishing buoys	−25.435	−48.705
	ESPBR167–23	CO1I/16S/28S	PEC	Mesohaline	20	Fishing buoys	−25.435	−48.705
	ESPBR015–21	CO1	Guaratuba Bay	Euhaline	35	Fishing buoys	−25.844	−48.582
	ESPBR016–21	CO1	Guaratuba Bay	Euhaline	35	Fishing buoys	−25.844	−48.582
	ESPBR017–21	CO1/16S	Guaratuba Bay	Mesohaline	18	Mud	−25.86	−48.64
	ESPBR018–21	CO1	Guaratuba Bay	Mesohaline	11	Mud	−25.859	−48.64
	ESPBR019–21	CO1/16S	Guaratuba Bay	Oligohaline	0	Mud	−25.868	−48.708
	ESPBR020–21	CO1	Guaratuba Bay	Mesohaline	11	Mud	−25.859	−48.64
	ESPBR021–21	CO1	Guaratuba Bay	Oligohaline	0	Mud	−25.868	−48.708
	ESPBR022–21	CO1	Guaratuba Bay	Polyhaline	24	Mud	−25.854	−48.571
	ESPBR023–21	CO1/16S	Guaratuba Bay	Polyhaline	20	Mud	−25.873	−48.606
	ESPBR024–21	CO1	Guaratuba Bay	Mesohaline	18	Mud	−25.86	−48.64
	ESPBR025–21	CO1	Guaratuba Bay	Polyhaline	24	Mud	−25.86	−48.597
	ESPBR026–21	CO1	Guaratuba Bay	Polyhaline	27	Mud	−25.864	−48.646
	ESPBR027–21	CO1	Guaratuba Bay	Polyhaline	24	Mud	−25.854	−48.571
	ESPBR028–21	CO1/16S	Guaratuba Bay	Polyhaline	24	Mud	−25.86	−48.597
	ESPBR030–21	CO1	Babitonga Bay	Polyhaline	27	Sand/mud	−26.264	−48.653
	ESPBR031–21	CO1	Babitonga Bay	Polyhaline	30	Fishing buoys	−26.275	−48.715
	ESPBR032–21	CO1	Babitonga Bay	Polyhaline	34	Organic matter on artificial piers	−26.249	−48.701
	ESPBR033–21	CO1	Babitonga Bay	Polyhaline	22	Mud	−26.3	−48.798
	ESPBR034–21	CO1	Babitonga Bay	Polyhaline	30	Fishing buoys	−26.275	−48.715
	ESPBR035–21	CO1	Babitonga Bay	Polyhaline	27	Sand/mud	−26.264	−48.653
	ESPBR036–21	CO1/16S	Babitonga Bay	Mesohaline	17	Mud	−26.307	−48.687
Alitta succinea	ESPBR007–21	16S	PEC	Polyhaline	23	Fishing buoys	−25.297	−48.331
	ESPBR008–21	CO1	PEC	Polyhaline	28	Sand/mud	−25.51	−48.468
	ESPBR009–21	CO1	PEC	Polyhaline	26	Sand/mud	−25.552	−48.395
	ESPBR010–21	CO1	PEC	Polyhaline	28	Sand/mud	−25.51	−48.468
	ESPBR011–21	CO1	PEC	Polyhaline	23	Fishing buoys	−25.297	−48.331
	ESPBR037–21	CO1	Babitonga Bay	Euhaline	32	Fishing buoys	−26.235	−48.641
	ESPBR038–21	CO1	Babitonga Bay	Euhaline	32	Fishing buoys	−26.235	−48.641
	ESPBR039–21	CO1	Babitonga Bay	Euhaline	34	Organic matter on artificial piers	−26.249	−48.701
	ESPBR040–21	CO1	Babitonga Bay	Polyhaline	27	Sand/mud	−26.296	−48.697
	ESPBR161–21	CO1	Babitonga Bay	Mesohaline	17	Mud	−26.3075	−48.687

Paranaguá Estuarine Complex (PEC), cytochrome c oxidase subunit I (CO1), 16S rRNA gene (16S), 28S rRNA gene (28S).

Table III. Genetic diversity of the species found in the study area. Abbreviations: n, Number of sequences; hap, number of haplotypes; Hd, haplotype diversity; π, nucleotide diversity. The table includes Tajima’s D, Fu’s FS and their respective p values.

Species	Population	n	Hap	Hd	Pi	Tajima’s D	p value	Fu’s FS	p-value
Alitta yarae sp.nov.	Total	32	11	0.813	0.002	−1.681	0.030	−6.010	0.000
	Babitonga Bay	7	5	0.905	0.003	–	–	–	–
	Guaratuba Bay	14	6	0.835	0.003	–	–	–	–
	PEC	11	6	0.800	0.002	–	–	–	–
Alitta succinea	Total	9	6	0.833	0.010	0.047	0.549	0.380	0.545
	Babitonga Bay	4	2	0.500	0.001	–	–	–	–
	PEC	5	5	1.000	0.015	–	–	–	–

Figure 6. Haplotype network based on CO1 for Alitta succinea and A. yarae sp. nov. Each haplotype is represented by a circle, the size of which corresponds to the number of haplotypes as indicated in the displayed scale. Colours indicate the geographic location of the haplotype. Numbers in parentheses refer to the relative haplotype (see Suppl. Table S3).