Redescription and review of the most abundant conehead in Italy: Acerentomon italicum Nosek, 1969 (Protura: Acerentomidae)

Figures & data

Table I. List of primer pairs used in the present study.

Primer cocktail	Primer	Direction	Sequences (3ʹ–5ʹ)
No	ProtF4/1	Forward	CTCRACTAACCATAARGATATCGG
No	CamF1	Forward	CTCRACTAACCATAARGATATTGG
Yes	GlomF1	Forward	Prot F4/1 + CamF1 (1:1)
No	ProtR2	Reverse	gtaaayatatgatgrgctc
No	DiplR1	Reverse	GCAATAATTATDGTDGCTGC
No	JapR1	Reverse	TAYACTTCDGGGTGBCCAAAGAATC
No	CamR1	Reverse	TAAACTTCDGGRTGDCCAAAAAATC
No	ProtR1	Reverse	TAAACTTCWGGRTGSCCAAARAATC
Yes	GlomR1	Reverse	JapR1 + CamR1 + ProtR1 (1:1:1)

Figure 1. Acerentomon italicum Nosek, 1969 Head. A, Dorsal view, setae sd4 and sd5 are labeled, arrow indicates pore; B, detail of frontal pore (scanning electron microscope, SEM); C, pseudoculus (from Nosek 1969); D, canal of maxillary gland (from Nosek 1969); E, maxillary glands (interference contrast microscope); F, maxillary and labial palpus (from Nosek 1969); G, labial palp sensillum (SEM).

Figure 2. Acerentomon italicum Nosek, 1969 Foretarsus: main sensilla (a-g, a′-c′, t1, t3) and setae α7 and γ3 are labeled (see text). A, Exterior view, arrows indicate pores (from Nosek 1969); B, external side sensilla (interference contrast microscope); C, external side sensilla, arrow indicates pore near sensillum c (scanning electron microscope, SEM); D, detail of claw (SEM); E, pore near sensillum t3 (SEM); F, interior view.

Figure 3. Acerentomon italicum Nosek, 1969. Scanning electron microscope (SEM) details of A, hind legs; B, abdominal appendage I; C, abdominal appendage III; D, striate band on abdominal segment VIII.

Table II. Chaetotaxy of Acerentomon italicum Nosek, 1969.

	Imago and pre-imago		Maturus junior		Larva II		Larva I
	Formula	Complementary setae	Formula	Complementary setae	Formula	Complementary setae	Formula	Complementary setae
Dorsal
Thorax I	4	1, 2	As imago		4	1, 2	4	1, 2
II	8/16	A2, 3, 4, M P1, 1a, 2, 2a, 3, 3a, 4, 5	As imago		6/14	A2, 4, M P1, 1a, 2, 3, 3a, 4, 5	6/10	A2, 4, M P1, 2, 3, 4, 5
III	10/16	A2, 3, 4, 5, M P1, 1a, 2, 2a, 3, 3a, 4, 5	As imago		6/14	A2, 4, M P1, 1a, 2, 3, 3a, 4, 5	6/10	A2, 4, M P1, 2, 3, 4, 5
Abdomen I	6/14	A1, 2, 3 P1, 1a, 2, 2a, 3, 3a, 4	As imago		2/14	A1 P as imago	0/8	P1, 2, 3, 4
II–VI	10/16	A1, 2, 3, 4, 5 P1, 1a, 2, 2a, 3, 4, 4a, 5	As imago		2/16	A1 P as imago	0/10	P1, 2, 3, 4, 5
VII	12/16	A1, 2, 3, 4, 5, x P1, 1a, 2, 2a, 3, 4, 4a, 5	10/16	Missing seta X	4/16	A1, 4 P as imago	0/10	P1, 2, 3, 4, 5
VIII	8/15	A1, 2, 4, 5 Pc, 1, 1a, 2, 2a, 3, 3a, 5	As imago		2/15	A4 P as imago	0/12	P1, 2, 2a, 3, 3a, 5
IX	14	1, 1a, 2, 2a, 3, 3a, 4	12	Missing 1a	8	1, 2, 3, 4	9
X	10	1, 2, 2a, 3, 4	8	Missing 2a	9
XI	6	1, 3, 4	As imago
XII	9		As imago
Ventral
Thorax I	(4 + 4)/6	A1, 2, M1, 2 P1, 2, 3	(4 + 2)/6	Missing M2	(2 + 2)/4	A1, M1 P1, 3	(2 + 2)/4	A1, M1 P1, 3
II	(5 + 2)/4	Ac, 2, 3, M P2, 3	As imago		(5 + 2)/2	Ac, 2, 3, M P2	(3 + 2)/2	Ac, 3, M P2
III	(7 + 2)/4	Ac, 2, 3, 4, M P2, 3	As imago		(5 + 2)/2	Ac, 2, 3, M P2	(3 + 2)/2	Ac, 3, M P2
Abdomen I	3/4	Ac, 2 P1, 1a	As imago		1/2	Ac P1	0/2	P1
II	5/5	Ac, 2, 3 Pc, 1a, 2	3/5	Missing A3	1/5	Ac Pc, 1a, 2	0/3	Pc, 2
III	7/5	Ac^1, 1, 2, 3 Pc, 1a, 2	3/5	Ac, 2 P as imago	1/5	Ac Pc, 1a, 2	0/3	Pc, 2
IV–VI	7/8	Ac, 1^2, 2, 3 P1, 1a, 2, 3	5/8	Missing A1	1/8	Ac P as imago	1/4	Ac P2, 3
VII	5/8	Ac, 2, 3 P1, 1a, 2, 3	As imago		1/8	Ac P as imago	1/4	Ac P2, 3
VIII	4/2	A1, 2 P1a	As imago		4/0	A1, 2	2/0	A2
IX	4	1, 2	As imago		4		8
X	4	1, 2	As imago		8
XI	6	1, 2, 3	As imago
XII	6		As imago

¹Absent in the holotype; ²Asymmetrically absent on sternite VI in the holotype.

Figure 4. Acerentomon italicum Nosek, 1969. Tergites: pores (al = anterolateral, asl = anterosublateral, l = lateral, psl = posterosublateral, psm = posterosubmedial, sam = sternal anteromedial, spsl = sternal posterosublateral, spsm = sternal posterosubmedial), anterior (A) and posterior (P) setae are labeled. A, nota; B, chaetotaxy of larva II nota (interference contrast microscope); C, abdominal tergites V–VII; D, detail of pores on tergite VII (scanning electron microscope, SEM); E, porotaxy on abdominal segment VII (interference contrast microscope).

Figure 5. Acerentomon italicum Nosek, 1969. Last abdominal segments: pores are labeled (ac = anterocentral, psm = posterosubmedial). A, tergites VIII–XII; B, comb on tergite VIII (from Nosek 1969); C, hind border of pleurite VIII (from Nosek 1969); D, detail of pore psm on tergite VIII (scanning electron microscope, SEM); E, detail of hind border of pleurite VIII (SEM).

Figure 6. Acerentomon italicum Nosek, 1969. A, prosternum; B, mesosternum, sternal central (sc) pore is labeled; C, abdominal sternites V–VII, pores are labeled (sam = sternal anteromedial, sc = sternal central, spsl = sternal posterosublateral, spsm = sternal posterosubmedial); D, pleural pectines VI and VII (from Nosek 1969), anterolateral (al) pore is labeled; E, pleural pectines VI (interference contrast microscope).

Figure 7. Acerentomon italicum Nosek, 1969. A, abdominal sternites VIII–XII, sternal anterolateral (sal) pores are labeled; B, male squama genitalis (from Nosek 1969); C, female squama genitalis; D, detail of female squama genitalis (interference contrast microscope); E, example of chaetotaxy anomaly of sternite VIII, with four posterior setae (interference contrast microscope).

Table III. Porotaxy of Acerentomon italicum Nosek, 1969. Legend: ac = anterocentral, al = anterolateral, asl = anterosublateral, l = lateral, psl = posterosublateral, psm = posterosubmedial, sal = sternal anterolateral, sam = sternal anteromedial, sc = sternal central, spsl = sternal posterosublateral, spsm = sternal posterosubmedial.

	Imago
	Formula	Pores
Dorsal
Thorax I	0
II	2 + 2	al, l
III	1 + 1	l
Abdomen I	1 + 1	psm
II–VI	3 + 3	psm, psl, al
VII	3 + 3	psl, asl, al
VIII	1 + 1	psm
IX–XI	0
XII	1	ac
Ventral
Thorax I	0
II–III	n	sc
Abdomen I–V	1	sc
VI	n + (1 + 1)	n sam, spsm
VII	n + (2 + 2)	n sam, spsm, spsl
VIII–XI	0
XII	1 + 1	sal

Table IV. Main measures and ratios of pre-imaginal stages of Acerentomon italicum Nosek, 1969; measures are given in µm (mean values ± standard deviation, variation interval in parentheses). Legend: LR = labrum ratio, PR = pseudoculus ratio, CF = distal part of “filamento di sostegno” (= maxillary gland) ratio (see text), TR = tarsus ratio, BS = sensilla t1 position relative to the base of tarsus (see text).

	Pre-imago	Maturus junior	Larva II	Larva I
n	5	6	5	4
Body length	1497.4 ± 56.8 (1419–1562)	1414.5 ± 111.3 (1210–1544)	993 ± 92.8 (899–1140)	837.3 ± 35.0 (785–858)
Head length	165.8 ± 8.2 (156–173)	154.3 ± 14.4 (138–165)	131.6 ± 3.3 (128–137)	112.8 ± 4.9 (109–120)
Rostrum length	46.5 ± 3.1 (43–50)	38.7 ± 1.2 (38–39)	35.5 ± 1.3 (34–37)	28.0 ± 1.2 (27–29)
LR	3.6 ± 0.1 (3.5–3.8)	4.0 ± 0.3 (3.6–4.2)	3.7 ± 0.1 (3.5–3.9)	4.0 ± 0.2 (3.8–4.2)
Pseudoculus diameter	9.8 ± 0.8 (9–11)	9.5 ± 0.5 (9–10)	8	6.8 ± 0.5 (6–7)
PR	17.1 ± 1.0 (15.6–18.0)	15.9 ± 0.6 (15.2–16.5)	16.4 ± 0.4 (16.0–17.1)	16.8 ± 1.3 (15.6–18.5)
Maxillary glands	18.0 ± 1.4 (16–20)	16.7 ± 2.1 (13–19)	14.8 ± 0.8 (14–16)	15.3 ± 0.5 (15–16)
CF	9.0 ± 0.7 (8.1–9.6)	9.6 ± 1.1 (8.7–10.6)	8.9 ± 0.3 (8.6–9.4)	7.4 ± 0.4 (6.9–8)
Tarsus length	107.2 ± 7.2 (99–118)	97.7 ± 4.8 (89–103)	82.8 ± 2.5 (81–86)	70.8 ± 1.5 (70–73)
Claw length	38.4 ± 3.7 (35–44)	35.5 ± 1.7 (34–37)	31.4 ± 0.5 (31–32)	29.3 ± 2.1 (27–32)
TR	2.8 ± 0.2 (2.7–3.1)	2.7 ± 0.1 (2.6–2.9)	2.6 ± 0.1 (2.5–2.8)	2.4 ± 0.1 (2.3–2.6)
Distance sensillum t1 base of tarsus	39.0 ± 2.6 (36–43)	34.2 ± 2.6 (30–37)	27.0 ± 1.6 (25–29)	23.5 ± 1.3 (22–25)
BS	0.57 ± 0.03 (0.53–0.62)	0.53 ± 0.03 (0.50–0.57)	0.48 ± 0.02 (0.45–0.51)	0.50 ± 0.04 (0.46–0.56)

Table V. List of representatives of Acerentomon italicum, used primer pair and Barcode of Life Data systems (BOLD) accession number analysed in the present study.

Ind. ID	Geography	Locality name	Coll. date	Primer pair	BOLD no.	Voucher
1412	ITALY: Liguria, Savona, Bergeggi	Monte Sant’Elena	24 May 2012	GlomF1/ProtR2	PROIT001-15	Yes
1414	ITALY: Liguria, Savona, Bergeggi	Monte Sant’Elena	24 May 2012	GlomF1/ProtR2	PROIT002-15	Yes
2829	ITALY: Liguria, Savona, Bergeggi	Monte Sant’Elena	24 May 2012	GlomF1/ProtR2	PROIT003-15	Yes
2833	ITALY: Liguria, Savona, Bergeggi	Monte Sant’Elena	24 May 2012	GlomF1/ProtR2	PROIT004-15	Yes
2835	ITALY: Liguria, Savona, Bergeggi	Monte Sant’Elena	17 October 2012	GlomF1/ProtR2	PROIT005-15	Yes
2836	ITALY: Liguria, Savona, Bergeggi	Monte Sant’Elena	17 October 2012	GlomF1/ProtR2	PROIT006-15	Yes
2837	ITALY: Liguria, Savona, Bergeggi	Monte Sant’Elena	17 October 2012	GlomF1/ProtR2	PROIT007-15	Yes
3057	ITALY: Liguria, Genova, Chiavari	Sanctuary Nostra Signora Delle Grazie	1 April 2014	GlomF1/GlomR1	PROIT008-15	Yes
3062	ITALY: Liguria, Genova, Chiavari	Sanctuary Nostra Signora Delle Grazie	1 April 2014	GlomF1/GlomR1	PROIT009-15	Yes
3063	ITALY: Liguria, Genova, Chiavari	Sanctuary Nostra Signora Delle Grazie	1 April 2014	GlomF1/DiplR1	PROIT010-15	Yes
3067	ITALY: Liguria, Genova	Ospedale S. Martino	1 April 2014	GlomF1/GlomR1	PROIT011-15	Yes
3069	ITALY: Liguria, Genova	Ospedale S. Martino	1 April 2014	GlomF1/DiplR1	PROIT012-15	Yes
3072	ITALY: Liguria, Genova	Ospedale S. Martino	1 April 2014	GlomF1/DiplR1	PROIT013-15	Yes
3077	ITALY: Liguria, Genova	Ospedale S. Martino	1 April 2014	GlomF1/GlomR1	PROIT014-15	Yes
3078	ITALY: Liguria, Genova, Chiavari	Sanctuary Nostra Signora Delle Grazie	1 April 2014	GlomF1/GlomR1	PROIT015-15	Yes
3079	ITALY: Liguria, Genova, Chiavari	Sanctuary Nostra Signora Delle Grazie	1 April 2014	GlomF1/DiplR1	PROIT016-15	Yes
3080	ITALY: Liguria, Genova, Chiavari	Sanctuary Nostra Signora Delle Grazie	1 April 2014	GlomF1/DiplR1	PROIT017-15	Yes
3086	ITALY: Liguria, Genova, Chiavari	Sanctuary Nostra Signora Delle Grazie	1 April 2014	GlomF1/GlomR1	PROIT018-15	Yes
3089	ITALY: Liguria, Genova	Ospedale S. Martino	1 April 2014	GlomF1/DiplR1	PROIT019-15	Yes
3098	ITALY: Liguria, Genova	Ospedale S. Martino	1 April 2014	GlomF1/GlomR1	PROIT020-15	Yes
3099	ITALY: Liguria, Genova	Ospedale S. Martino	1 April 2014	GlomF1/GlomR1	PROIT021-15	Yes
HP132	AUSTRIA: Lower Austria	Leopoldsberg		CamF1/DiplR1	PROAT052-12	Yes

Figure 8. Acerentomon italicum Nosek, 1969. DNA Barcoding. Neighbour-joining (NJ) tree based on Kimura 2 Parameter (K2P) distances from 21 representatives of A. italicum from three collection sites in Liguria.

Nosek J. 1969. Three new species of Protura from Italy. Atti dell’Istituto Veneto di Scienze, Lettere ed Arti. Classe di Scienze matematiche e naturali 127:485–494.

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