Xiphinema browni

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Taxonavigation

Ordo: Dorylaimida
Familia: Longidoridae
Genus: Xiphinema

Name

Xiphinema browni Lazarova & Peneva & Kumari, 2016 sp. n. – Wikispecies link – ZooBank link – Pensoft Profile

• Xiphinema pachtaicum (Tulaganov, 1938) Kirjanova, 1951 apud Kumari et al. 2005, syn. n.

Measurements

See Tables 3–5.

Table 3. Morphometrics of Xiphinema browni sp. n (localities in the Czech Republic and Slovakia) and Xiphinema pachtaicum (Bulgaria). All measurements in micrometres, except ratios given as mean ± standard deviation (range).

		Xiphinema browni sp. n					Xiphinema pachtaicum
Locality		Kurdějov	Sokolnice		Mohyla míru	Moča	Balgarene
Plant host		grapevine	grapevine		apple	grapevine	pear
n	Holotype	50 females	20 females	male	12 females	4 females	6 females
L	1904	2031±123 (1798–2408)	1886±89	1849	1972±90	1715±142	1735±232
			(1751–2099)		(1785–2079)	(1603–1922)	(1522–2015)
a	57.8	69.3±5.16	60.5±4.4	73.9	60.1±3.14	69.5±6.57	58.7±4.9
		(56.9–81.3)	(52.3–69.9)		(55.6–64.5)	(63.6–76.3)	(53.3–65.7)
b	6.7	7.3±0.76	6.9±0.38	6.9	7.0±0.32	8.2, 6.8	5.9±0.5
		(6.1–8.7)	(6.4–7.9)		(6.4–7.4)		(5.3–6.4)
c	64.8	69.9±6.22	65.8±5.71	54.4	64.9±3.41	61.6±8.72	58.2±8.3
		(54.7–83.0)	(56–79.6)		(58.5–70.3)	(53.4–73.9)	(50.9–66.3)
c’	1.9	1.78±0.12	1.82±0.14	1.89	1.8±0.08	1.8±0.17	1.7±0.1
		(1.53–2.07)	(1.61–2.13)		(1.6–1.9)	(1.5–1.9)	(1.6–1.8)
V/Spicule length	56.1	55±1.30	55±1.71	29.0	55.4±1.15	55.5±1.16	58.6±1.4
		(52.3–58.5)	(49–57)		(53.8–58.1)	(53.8–56.4)	(57.0–60.4)
Odontostyle	84	83±2.2	79±2.6	76	82±3.39	77±4.69	84.2±3.7
		(78–86)	(74–83)		(73–85)	(72–81)	(78–88.5)
Odontophore	43	42±1.69	41±0.91	38	43±1.88	38±3.30	48.9±2.1
		(38–48)	(39–43)		(39–46)	(35–42)	(46–51)
Oral aperture to	72	71±2.56	68±2.35	67	71±1.68	66±5.06	76.8±3.4
guide ring		(65–75)	(63–72)		(67–73)	(60–72)	(73–80)
Tail length	29	29±1.94	29±2.24	34	30±0.82	28±1.63	29.8±0.9
		(25–33)	(24–32)		(29–32)	(26–30)	(28–30)
Length of hyaline	8	8±1.28	8±1.22	10	8±0.68	8±1.41	8.7±1.0
part		(6–12)	(6–10)		(7–9)	(7–10)	(8–10)
Body diam. at:	8	8±0.58	8±0.51	9	9±0.43	8±0.50	8.8±0.2
- lip region		(8–10)	(8–9)		(8.5–10)	(7–8)	(8.5–9)
- guiding ring	22	20±0.67	19±0.49	19	22±1.44	19±1.41	21.5±1.0
		(19–21)	(19–20)		(19.5–24)	(18–21)	(20.5–23)
- base of pharynx	29	26±1.58	26±2.41	23	28±1.69	23.1, 23.8	26.5±1.2
		(22–32)	(19–20)		(25–30)		(25–28)
- mid body	33	29±2.78	31±2.58	25	34±2.66	25±1.89	28.9±2.1
		(25–38)	(26–37)		(29–38.5)	(22–26)	(26–32)
- anus	16	16±0.97	16±0.92	18	17±0.89	16±0.96	17.1±1.0
		(14–19)	(15–18)		(16–19)	(15–17)	(16–19)
- beginning of	7.5	7±1.11	7±0.62	8		8±1.50	8.7±0.0
hyaline part		(5–10)	(6–8)			(6–9)	(9–9)

Table 4. Pharyngeal characters of females of Xiphinema americanum group species studied from different localities.

	Xiphinema browni sp. n.			Xiphinema pachtaicum	Xiphinema penevi sp. n.	Xiphinema parasimile Lazarova et al. (2008)
Locality Character	Kurdějov, Czech Republic	Sokolnice, Czech Republic	Mohyla míru, Czech Republic	Balgarene, Bulgaria	Ifrane, Morocco	Vinogradets, Bulgaria	Ralja, Serbia Paratypes
n	50	20	5	5	6	14	5
Pharynx length (μm)	278.0±17.9 (236–309)	272.0±12.1 (247–297)	271.4±20.1 (234–294)	303.5±13.5 (291–317)	274.4±29.2 (229–308)	250.5±21.0 (233–311)	282.2±2.1 (260–310)
Bulbus length (μm)	60±3.48 (53–69)	59±3.02 (56–67)	60±2.88 (56–63)	75, 77, 80	68.4±2.7 (65–72)	59.8±3.5 (55.5–68)	61.6±4.8 (56–63)
Bulbus width (μm)	13±1.30 (9–16)	13±1.21 (11–16)	14±1.14 (12–15)	15, 15, 16	13.6±0.8 (12–14)	12.0±0.6 (11–13)	14.4±0.5 (14–15)
Bulbus length/ Pharynx length (%)	21.7± 1.7 (17.4–27.1)	21.8±1.6 (19.5–27.1)	22.3±1.3 (20–24)	25.6±07 (25–26)		24.2±2.3 (19–28) n=11	21.8±0.7 (20.7–22.6)
DN* (%)	17.5±1.9 (15.3–21.1) n=6	13.1±2.3 (12.7–17.3) n=5	12.5, 13.0, 14.9	9.3, 10.3	11.4±1.4 (9.9–12.9)	16.7±3.3 (13.6–18.6) n=8	16.5–17.7
DO* (%)	10.9±1.7 (8.8–13.8) n=6	7.9±3.8 (5.5–15.6) n=5	11.9±1.8 (8.8–13.3) n=5	11.5, 12.0	12.1±1.6 (9.9–13.2)	11.1, 13.6	11.6–14.6
SVN1* (%)		53.9±1.6 (51.8–55.0)	55.6, 54.4	60.3	56.7±2.0 (53.8–58.8)		55.3–59.7
SVN2* (%)		53.2			58.7±2.9 (55.4–61.0)		57.3–60.1
SVO (%)	74.2±1.9 (71.4–75.4) n=4	74.9±3.3 (67.6–76.4) n=5	68.5, 71.1, 71.8	72.0, 74.4	75.4±2.4 (73.5–79.4)
Glandularium ** (μm)	48.5±1.9 (46–52) n= 8	50.6±2.3 (48–51) n=5	53, 48, 46	68, 70, 70	61.9±3.1 (57–65) n=8	49.9±1.4 (48–52) n=8	52.3±2.2 (52–56)

Table 5. Measurements of uteri (including ovejector), ovejector and vaginal parts. All measurements in micrometres presented as mean ± standard deviation (range).

	Characters Locality	Anterior uterus	Posterior uterus	Ovejector	Vagina length	Pars distalis vaginae	Pars proximalis vaginae
Xiphinema browni	Kurdějov	42.1±5.7 (35–54) n=8	38.9±5.0 (31–43) n=7	26	12.9±1.4 (11–15) n=9	6.7±1.1 (5.5–8.5) n=6	13.7±0.6 (13–14) n=3
	Sokolnice	45.5±3.7 (38–46) n=4	46.0±4.0 (40–49) n=4	30.5		5, 6, 6	8.5, 10, 10
	Mohyla míru	39, 40, 50	39, 41.5, 44	26, 33	12.5±1.0 (11–14) n=5	5, 6	10, 10
Xiphinema penevi	Ifrane	52.2±9.0 (36–68)	52.3±4.3 (46–58)	26		8.9±0.3 (8–9)	10.6±1.2 (8–13)
Xiphinema pachtaicum	Balgarene	40, 48	42, 49, 50	37	13, 14, 15	9, 9	12, 12
Xiphinema parasimile	Vinogradets	33.1±0.4 (30–38) n=13	31.2±0.7 (24–39) n=13	29.4±4.3 (26–33.5) n=10	14.5±1.7 (13–15) n=17	7.4±0.5 (7–8) n=15	7.4±0.5 (7–9) n=19
	Ralja,Trešna paratypes	40.0±11.3 (27–46) n=3	-	-	14.5±1.05 (13–16) n=5	7.8±0.8 (7–8.5) n=3	8.75±0.3 (8.5–9) n=4
Xiphinema simile	Srebarna, Bulgaria	18.8±2.8 (14–21) n=6	18.5±2.4 (15–20) n=6	36.3±6.4 (29–41) n=3	14.8±1.3 (13–16) n=5	5.8±0.4 (5.5–6) n=8	9.5±0.9 (8.5–11) n=7
	Kalimok- Brashlen Bulgaria	21.8±1.9 (16.5–24) n=14	21.5±1.8 (19–24) n=14	43.1±3.1 (36.5–48) n=12	16.8±0.8 (15–18) n=15	6.4±0.65 (5.5–7) n=17	8.6±0.5 (8–10) n=17
	Orlyane Bulgaria	21.75±2.2 (17–24) n=7	22.1±2.3 (19–26) n=7	43.8±4.2 (36–50) n=7	16.9±1.1 (15–18) n=8	6.05±0.6 (5.5–7) n=11	9.05±0.8 (8–10) n=10
	Kamen bryag Bulgaria	23.0±4.8 (18–30) n=5	24.2±4.15 (19–30) n=5	47.2±8.9 (37–60) n=5	15.9±1.8 (13–17) n=5	6.4±0.6 (6–7) n=5	9.8±0.8 (9–10) n=5

Description

Females. Body slender C to open spiral shaped. Cuticle with fine transverse striae. Thickness of the cuticle at postlabial region 1–1.5 μm, 1.5 rarely 2 μm at mid-body and 2 μm at post-anal region. Labial region set-off from the rest of the body by a constriction, expanded, rounded laterally, 5.0±1.1 (4–7) μm high. Amphideal fovea hardly visible, funnel-shaped, its opening c. 5 μm (50%) wide visible posterior the constriction level. Distance between first and second guide ring in specimens with retracted odonostyle 5–10 μm long. Odontophore with moderately developed basal flanges 6.1±0.6 (5.5–7) μm wide. A small vestigium observed occasionally in slender part of pharynx. Pharyngeal characters presented at Table 4. Dorsal pharyngeal gland nucleus 2 μm diam. Ventrosublateral nuclei barely visible. Rectum 20.8 ± 1.5 (18–23) μm, n=7, or c 1.3 times anal body diameter. Reproductive system amphidelphic, symbiont bacteria present in the ovaries. Separate uteri and ovejector present (Table 5), oviduct 90.5±13.0 (68–101) μm; vagina bell-shaped 39.5% of the corresponding body width (33–50%, n=14), vulva post-equatorial. Numerous sperm observed in one female from Kurdějov (Figs 2B, 4B). Tail conical, dorsally convex, ventrally straight or slightly concave with narrowly rounded to pointed terminus. Two pairs of caudal pores. Male. Very rare. One specimen found in Sokolnice population. Male similar to the female with posterior region more strongly curved. Lip region and tail shape as in females, differences were observed within body width and tail length, which reflected a and c’ values. Spicules robust, slightly curved, lateral guiding piece 7 μm long. Adanal pair preceeded by a row of 5 irregularly spaced supplements, the two anteriormost weakly developed. Tail conoid, ventrally straight, dorsally convex with pointed terminus, caudal pores not visible. The slide of the only male specimen, described by Kumari et al. (2005), was subsequently damaged.
Juveniles. The scatter diagram based on functional and replacement odontostyle, and body length revealed the presence of four juvenile stages (Fig. 8). Tail shape and length similar in all stages and females with c’ slightly decreasing in successive stages (Kumari 2005, Fig. 3, Table 3).

Type locality and plant association

Kurdějov, Břeclav County, South Moravia, Czech Republic, associated with grapevine. Other localities: Mohyla míru, Brno-Venkov County, South Moravia, the Czech Repbulic, in the rhizosphere of apple trees; Sokolnice, Brno-Venkov County, South Moravia, the Czech Repbulic, in the rhizosphere of grapevine; Moča, Komárno County, Nitra, Slovak Republic, in the rhizosphere of grapevine.

Type material

The holotype, 9 paratype females and juveniles from all stages are deposited in the nematode collection of the Institute of Biodiversity and Ecosystem Research, Sofia, Bulgaria. Other paratypes deposited as follows: 15 females in the Crop Research Institute, Prague, the Czech Republic; 5 females in the USDA Nematode Collection, Beltsville, Maryland, USA; 5 females in the Nematode Collection of the Institute of Plant Protection, Bari, Italy; 5 females in the Wageningen Nematode Collection (WANECO), Wageningen, the Netherlands. The ribosomal and mtDNA sequences (18S rDNA, ITS1, ITS2, D2-D3, cox1, nad4) of Xiphinema browni sp. n. are deposited in GenBank (for accession numbers see Table 2).

Sequence and phylogenetic analyses

There was no sequence variation between populations for 18S and D2-D3, ITS1 and ITS2 rDNA regions of Xiphinema browni sp. n. Of all four populations studied cox1 region of three population from the Czech Republic (Kurdějov, Mohyla Míru, Sokolnice) were sequenced by Kumari et al. (2010b) and all populations were identical therefore only one population was submitted to GenBank (accession number GU222424). The Slovakian population was sequenced in this study and it was identical to previously published sequence of Kurdějov the population identified as Xiphinema pachtaicum (GU222424, Kumari et al. 2010b). All four sequenced populations were also identical for nad4 part.
BLAST at NCBI using 18S and D2-D3 region sequences as queries revealed highest similarity (99 and 87%) to the corresponding sequences of Xiphinema simile Lamberti, Choleva & Agostinelli, 1983 from Serbia (AM086681) and two Spanish populations of Xiphinema opisthohysterum Siddiqi, 1961 (JQ990040 and KP268967), respectively. The estimated divergences (p-distance) between the 18S rDNA sequences of the new species and the closest species, Xiphinema parasimile from Bulgaria (this study) and Xiphinema simile from Serbia (AM086681) were 0.3 (6 nt) and 1.2% (21 nt), respectively. Again, the new D2-D3 sequence of Xiphinema parasimile from Bulgaria was most similar (p-distance = 4.6%), followed by the Serbian populations of Xiphinema parasimile (p-distance = 7.6–7.9%, calculated for D2 region only) and various populations of Xiphinema simile (14.1–14.7%). The partial cox1 sequences of Xiphinema browni sp. n revealed highest similarity to Xiphinema simile from Slovakia (AM086708). Surprisingly, these two species showed very high similarity 99% (2 nts difference) in cox1 sequences and higher dissimilarity in 18S rDNA (p-distance = 1.2%, 21 nts). Other authors (Gutiérrez-Gutiérrez et al. 2012) have also reported similar observation namely, 100% identity in cox1 part of two different species Xiphinema duriense Lamberti, Lemos, Agostinelli & D’Addabo, 1993 (JQ990053) and Xiphinema opistohysterum (JQ990054) and clear separation in D2-D3 28S sequences (or 96 % identity). Further, the cox1 sequences of Xiphinema browni sp. n. and the closest species Xiphinema parasimile, Xiphinema simile (GU222425, Czech Republic) and Xiphinema pachtaicum (HM921369, Spain) were translated to amino acids and aligned (Fig. 9). The estimated p-distances between Xiphinema browni sp. n. and the three species were 10.1%, 21.7% and 23.3%, respectively. In all three phylogeny reconstructions (18S, D2-D3 and cox1) Xiphinema parasimile from Bulgaria was a sister species of Xiphinema browni sp. n. and both species were part of a well supported clade with other European populations of Xiphinema simile (Figs 10–12). The recently described species Xiphinema vallense Archidona-Yuste, Navas-Cortes, Cantalapiedra-Navarrete, Palomares-Rius & Castillo, 2016 presented only with D2-D3 and ITS1 rDNA sequences seems also to be evolutionary very closely related (Figs 11 and 13), however amplifying additional sequences for other molecular markers (e.g. 18S and cox1) could help to better clarify its relationships. The position of the new species in the phylogeny trees based on ITS1 and ITS2 sequences was unstable (Figs 13 and 14). The analyses resulted in various tree topologies when using different alignment algorithms and reconstruction methods (ML and BI) and because of the absence of homologous sequences from closely related species. In most cases Xiphinema browni sp. n. was part of a clade of European Xiphinema americanum-group species considered as group II in a previous publication (Archidona-Yuste et al. 2016). Due to insufficient number of nad4 sequences of species belonging to the Xiphinema americanum-group at NCBI no phylogenetic reconstructions are presented. Diagnosis and relationships. Xiphinema browni sp. n. is characterised by a unique combination of traits: slender and medium sized body (1.6–2.41 mm) and odontostyle (73–85 μm), lip region expanded, laterally rounded, separated from the rest of body by a constriction, post-equatorial vulva position (V=52–58 %), symbiotic bacteria present, female tail conical dorsally convex, with narrow rounded to pointed tip, 24–35 μm long, (c=53.4–86.8; c’=1.5–2.1), and specific ribosomal and mtDNA sequences (Table 2). The alpha-numeric codes based on average values (ranges given in parentheses) using the polytomous key by Lamberti et al. (2004) are: A3 (2), B3 (2), C3 (4), D2 (1/3), E2 (3), F2 (1/3), G2, H1, I2 (1/3).
Species having similar morphometrics to Xiphinema browni sp. n. based on type populations are presented in Table 6. Recently described species Xiphinema parasimile, Xiphinema parabrevicolle Gutiérrez-Gutiérrez, Cantalapiedra-Navarrete, Decraemer, Vovlas, Prior, Palomares-Rius & Castillo, 2012, Xiphinema parapachydermum Gutiérrez-Gutiérrez, Cantalapiedra-Navarrete, Decraemer, Vovlas, Prior, Palomares-Rius & Castillo, 2012, Xiphinema paratenuicutis Gutiérrez-Gutiérrez, Cantalapiedra-Navarrete, Decraemer, Vovlas, Prior, Palomares-Rius & Castillo, 2012, Xiphinema plesiopachtaicum Archidona-Yuste, Navas-Cortes, Cantalapiedra-Navarrete, Palomares-Rius & Castillo, 2016 and Xiphinema vallense (Barsi and Lamberti 2004, Gutiérrez-Gutiérrez et al. 2012, Archidona-Yuste et al. 2016) have also been compared. Six of these species have non-European distribution (Table 6) whereas the others were described from and/or found mainly in Europe. Xiphinema simile was also included in the table comparing morphometrical data because of the close relationships based on sequence and phylogenetic analyses and its wide distribution in many European countries.

Table 6. Morphometric data of Xiphinema americanum species having similar morphometrics with the new species based on type populations.

	Non-European species							European species
	Xiphinema penevi sp. n.	Xiphinema bricolensis	Xiphinema californicum	Xiphinema citricolum	Xiphinema intermedium	Xiphinema oxycaudatum	Xiphinema tenuicutis	Xiphinema plesiopachtaicum
Body L	1.69 (1.5–1.85)	1.9 (1.7–2.3)	2 (1.8–2.2)	1.6–1.8	1.6 (1.4–1.9)	1.6 (1.5–1.7)	1.8 (1.6–1.9)	1.9 (1.5–2.1)
a	61 (57.2–65.0)	56 (52–62)	60 (52–68)	45–46	43 (38–51)	47 (45–51)	46 (40–53)	64 (57.3–70.2)
c	57.7 (50.8–61.5)	57 (49–65)	63 (58–76)	44–50	47 (41–59)	51 (48–54)	61 (56–65)	71.1 (62.5–88.7)
c’	1.8 (1.6–1.9)	1.5 (1.3–1.6)	1.6 (1.3–1.9)	1.6–1.7	1.5 (1.3–1.7)	1.6 (1.3–1.7)	1.5 (1.4–1.7)	1.4 (1.3–1.7)
Vulva [%]	57 (51–61.5)	52 (50–55)	51 (49–55)	52–54	52 (50–57)	52.5 (51–54)	51 (47–52)	57.3 (55.5–60)
Odontostyle L	77 (72–79)	87 (85–94)	90 (83–98)	78–86	76 (68–80)	82 (78–84)	76 (73–80)	83 (77–89)
Tail L	29 (26–32)	36 (31–41)	31 (27–36)	34–36	33 (31–38)	33 (27–35)	29 (26–32)	26 (23–28)
Length to GR	68 (66–71)	68 (61–76)	76 (66–83)	64–72	63 (58–67)	71 (66–75)	60 (55–64)	69 (63–76.5)
Lips width	8 (8–9)	11	10 (10–11)	12.5	10.5 (9.5–11)	10 (9–10)	9 (9–10)	9.5 (8.5–10.5)
J	9 (8–10)	(6–7)	6 (5–8.5)	12–14	10 (9–12)	9 (7–10)	8 (6.5–10)	8 (5.5–10)
Juvenile stages	4	?	4	3		?		?
Males (number of VM supplements)	rare or absent	rare or absent 11	rare or absent 7	rare or absent 10	rare or absent 11	rare or absent 3	not found	Not found
	European species
	Xiphinema browni sp. n.	Xiphinema microstilum	Xiphinema pachtaicum	Xiphinema parasimile	Xiphinema paratenuicutis	Xiphinema simile	Xiphinema parapachydermum	Xiphinema vallense
Body L	2.03 (1.8–2.40)	2.6 (2.5–2.8)	1.88	1.99 (1.75–2.26)	2.01 (1.7–2.2)	1.9 (1.7–2.1)	1.78 (1.41–2.0)	2.0 (1.8–2.2)
a	69.3 (56.9–81.3)	86 (77–93)		70.5 (61.0–76.1)	61.1 (51.9–69.7)	71 (63–77)	64 (51.3–73.1)	68.9 (61.6–79.1)
c	69.9 (54.7–83.0)	74 (63–88)	72.3	59.9 (50.9–69.8)	68.8 (58.8–79.9)	67 (61–70)	60.3 (46.3–75.5)	73.4 (58.2–86.3)
c’	1.8 (1.53–2.07)	1.8 (1.6–2.0)	1.6	2.02 (1.79–2.28)	1.4 (1.2–1.6)	1.7 (1.6–1.8)	1.8 (1.5–2.3)	1.6 (1.4–1.7)
Vulva [%]	55 (52.3–58.5)	57 (55–60)	60	55.5 (52.2–58.7)	56.8 (55–60)	53 (51–54)	59 (55–66)	57.5 (55–59.5)
Odontostyle L	79 (75–83)	74 (68–77)	83	69.7 (64.4–73.7)	75.2(71.5–83)	66 (62–69)	81 (70–87.5)	79 (73–85.5)
Tail L	29 (25–33)	35 (31–39)	26	33.3 (30.3–37.1)	29.4 (25–34.5)	29 (27–30)	28.8 (26.5–35.5)	27.8 (22.5–34)
Length to GR	71 (65–75)	63 (57–68)	78	62.6 (59.4–66.3)	63.2 (60–69)	51 (49–53)	70 (59.5–75.5)	69.5 (62–72.5)
Lips width	8 (8–10)	9 (9–10)	10	9.0 (8.4–9.7)	9.6 (9–10)	9 (9–9)	8.8 (8–9.5)	8.5 (8–9)
J	8 (6–12)	10 (7–12)		8.2 (6- 10)	8.4 (6.5–10.0)	7 (6–8)	9.3 (7–12.5)	7.6 (6.5–8.5)
Juvenile stages	4		4	4	4	3	4	4
Males (number of supplements)	rare or absent 5	frequent 4–5	rare or absent 5–6	rare or absent 5	males abundant 5	rare or absent 3–5	Males abundant	Rare or absent 6, 7

Based both on morphology and molecular data Xiphinema browni sp. n. is most similar with Xiphinema parasimile, Xiphinema simile and Xiphinema vallense. Morphologically, it can be distinguished from:

Xiphinema parasimile by its different lip region shape (expanded vs not expanded), somewhat longer odontostyle av. 79–83 (73–85) μm vs av. 70 (64–74) μm in the type population, avs. 69–70 (63–74) in Bulgarian populations and avs. 68–70 (67–72) μm in females from Romania (Barsi and Lamberti 2004, Lazarova et al. 2008, Bontă et al. 2012);
Xiphinema simile by its longer odontostyle av. 79–83 (73–85) vs av. 66 (62–69) in type population, avs. 68.5–70 (66–72.5) in other Bulgarian populations, 67.5 (65–70) μm in a population from Bosna and Herzegovina, and avs. 67–68 (61–73) μm in females from the Czech Republic (Lamberti et al. 1983, Barsi and Lamberti 2004, Kumari 2006, Lazarova et al. 2008). However, it should be noted that females from Serbia and Crete (odontostyle 71.5 (66–74) μm and 75–77 μm, respectively) have slightly overlapping values between Xiphinema browni sp. n. and Xiphinema simile for this character (Barsi and Lamberti 2004, Tzortzakakis et al. 2014). Further Xiphinema browni sp. n. differs from Xiphinema simile in the length and structure of uteri (in the new species separate uteri and ovejector present vs separate uteri not present), different tail shape (conoid vs bluntly conoid), and in the shorter bulbus (53–69 vs 76–92 μm) (Lazarova et al. 2008) (Table 4). Finally, Xiphinema browni sp. n. develops though 4 vs 3 juvenile stages in Xiphinema simile;
Xiphinema vallense by the position of amphideal fovea aperture (posterior constriction level vs on the lips); higher lip region (4–7 μm vs 2–3.5 μm); presence of symbiont bacteria in ovaries vs ovaries without symbionts; somewhat higher c’ values (c’=1.8 (1.53–2.07) vs c’=1.6 (1.4–1.7); the different tail shape (dorsoventral depression at hyaline region level not present vs present); shorter spicules in males (29 μm vs 38 μm).
Additionally, Xiphinema browni sp. n. can be differentiated from:
Xiphinema pachtaicum by the different vagina shape (bell-shaped vs funnel shaped, (Figs 16, 18) and shorter pars distalis vaginae, shorter pharyngeal bulb (53–69 vs 75–80 μm), more posterior location of the dorsal nucleus (DN=13–21% vs 9–10 %) (Table 4), different tail shape in both sexes (conical vs subdigitate). Illustrations of selected features of the closest species Xiphinema pachtaicum, Xiphinema parasimile and Xiphinema penevi sp. n. are presented in Figs 15–18 for comparison. Xiphinema paratenuicutis in having symbionts in its ovaries vs absent, males rare vs abundant, higher values for c’ (1.8 (1.5–2.1) vs 1.4 (1.2–1.6), different location of dorsal nucleus (DN after beginning of the stronger cuticular lining of the bulbus vs before, see Fig. 1 D1-F and Fig. 2E in Gutiérrez- Gutiérrez et al. 2012);
Xiphinema plesiopachtaicum by the position of the amphideal aperture (posterior vs at the constriction level); somewhat shorter bulbus (avs. 59–60 (53–69) vs av. 73 (60–86); shorter uteri (av. 81 vs av. 138 μm); higher c’ values (c’=1.8 (1.53–2.07) vs c’=1.4 (1.3–1.7); and differently shaped vagina (bell-shaped vs funnel shaped).
For comparison between Xiphinema browni sp. n. and Xiphinema penevi sp. n. see below.

Etymology

The species is named after Prof Derek JF Brown, an outstanding nematologist, for his significant contributions to the knowledge of plant parasitic nematodes and the development of nematology in Bulgaria.

Original Description

• Lazarova, S; Peneva, V; Kumari, S; 2016: Morphological and molecular characterisation, and phylogenetic position of X. browni sp. n., X. penevi sp. n. and two known species of Xiphinema americanum-group (Nematoda, Longidoridae) ZooKeys, (574): 1-42. doi

Images

Figure 1. Xiphinema browni sp. n. Female: Variations in: A–C Anterior end D–F Pharyngeal bulbus G–I Tail shape A, D, G Kurdĕjov (type population) B, F, I Mohyla míru C, E, H Sokolnice. Scale bars: 25 μm  Figure 2. Xiphinema browni sp. n. Female: Variations in genital system: A, B Anterior genital branch C Posterior genital branch D–F Region of vagina and uteri A, B, D Kurdĕjov (type population) C, F Mohyla míru E Sokolnice. Scale bars: 25 μm.  Figure 3. Xiphinema browni sp. n. A–C Entire body (A, C females B male); Female: D–F Anterior ends G–I Pharyngeal bulbus J–M Tail shape variation A, F, I, M Mohyla míru B, E, H, L Sokolnice C, D, G, J, K Kurdĕjov (type population). Scale bars: (A–C) 400 μm; (D–M) 30 μm.  Figure 4. Xiphinema browni sp. n. Female: A–D Genital system (B uterus full with sperm) E–G Labial region (E Amphid F Female G Male) H Ovary with endosymbionts I, K–N Variations in vagina J Lateral field A, B, H, I, J Kurdĕjov C, G Sokolnice D, K, M Mohyla míru E, F, L, N Moča. Scale bars: 30 μm (A–D, H–J); 12 μm (E–G, K–N).  Figure 5. Xiphinema browni sp. n., Sokolnice. Male: A Anterior end B Pharyngeal bulbus C Posterior end D Spicules. Scale bars: 25 μm  Figure 6. Xiphinema browni sp. n., Kurdĕjov. Juveniles and female: A–E Anterior ends of first- to fourth-stage juveniles and female F–J Tails of first- to fourth- juvenile stages and female. Scale bar: 25 μm  Figure 7. Xiphinema browni sp. n. Kurdĕjov. Juveniles and female: A–E Anterior ends of first- to fourth-stage juveniles and female F–J Tails of first to fourth juvenile stages and female (G1 and G2 – second-stage juvenile). Scale bar: 30μm.  Figure 8. Scatter plot of odontostyle (■) and replacement odontostyle (□) against body length of Xiphinema browni sp. n. juveniles and females from Kurdĕjov population.  Figure 9. Cox1 amino acid sequence alignment of Xiphinema browni sp. n. and the closest species Xiphinema parasimile, Xiphinema simile and Xiphinema pachtaicum.  Figure 10. Hypothesis of the phylogenetic relationships of Xiphinema browni sp. n., Xiphinema parasimile, Xiphinema pachtaicum and Xiphinema penevi sp. n. based on 18S rDNA inferred from a Bayesian analysis using GTR+G model and Prionchulus punctatus (Cobb, 1917) Andrássy, 1958, Alaimus sp. and Tripylina sp. as an outgroup. Posterior probabilities higher than 0.8 are presented. The sequence of Xiphinema browni from Moča was not included due to the shorter length.  Figure 11. Hypothesis of the phylogenetic relationships of Xiphinema browni sp. n., Xiphinema parasimile, Xiphinema pachtaicum and Xiphinema penevi sp. n. based on 28S rDNA inferred from a Bayesian analysis using GTR+G model and Longidorus helveticus Lamberti, Kunz, Grunder, Molinari, De Luca, Agostinelli & Radicci, 2001 and Longidorus poessneckensis Altherr, 1974 as an outgroup. Posterior probabilities higher than 0.8 are presented.  Figure 12. Hypothesis of the phylogenetic relationships of Xiphinema browni sp. n. and Xiphinema parasimile based on cox1 inferred from a Bayesian analysis using GTR+G model and Xiphinema italiae Mayl, 1953 and Xiphinema diversicaudatum (Micoletzky, 1927), Thorne, 1939 as an outgroup. Posterior probabilities higher than 0.8 are presented.  Figure 13. Hypothesis of the phylogenetic relationships of Xiphinema browni sp. n. based on ITS1 inferred from a Bayesian analysis using GTR+G model and Xiphinema barense Lamberti, Roca, Agostinelli, Bleve-Zacheo, 1986, Xiphinema italiae and Xiphinema diversicaudatum as an outgroup. Posterior probabilities higher than 0.8 are presented.  Figure 14. Hypothesis of the phylogenetic relationships of Xiphinema browni sp. n., Xiphinema parasimile, Xiphinema pachtaicum and Xiphinema penevi sp. n. based on ITS2 inferred from a Bayesian analysis using GTR+G model and Xiphinema italiae, Xiphinema diversicaudatum and Xiphinema vuittenezi Luc, Lima, Weischer & Flegg, 1964 as an outgroup. Posterior probabilities higher than 0.8 are presented.  Figure 15. Xiphinema browni sp. n., Xiphinema penevi sp. n. Xiphinema pachtaicum and Xiphinema parasimile. Female: A–C Anterior ends D–F Tail shapes G–J Pharyngeal bulbs A, D, G Xiphinema browni sp. n. B, E, I Xiphinema penevi sp. n. C, F, J Xiphinema pachtaicum H Xiphinema parasimile. Scale bars: 25 μm  Figure 16. Xiphinema browni sp. n., Xiphinema penevi sp. n. and Xiphinema pachtaicum. Female genital system comparison: A, E Posterior genital branch B–D Anterior genital branch A, B Xiphinema browni sp. n. C Xiphinema penevi sp. n. D, E Xiphinema pachtaicum. Scale bars: 25 μm  Figure 17. Xiphinema browni sp. n., Xiphinema parasimile, Xiphinema pachtaicum and Xiphinema penevi sp. n. Female and male: A–D Anterior ends E–H Labial region I–K Pharyngeal bulbs L, M, R Male tails N–Q Female tails A, E, I, M, N Xiphinema browni sp. n. B, F, K, O, R Xiphinema parasimile C, G, J, L, P Xiphinema pachtaicum D, H, Q Xiphinema penevi sp. n. Scale bars: 30 μm (A–D, I–R); 12 μm (E–H).  Figure 18. Xiphinema browni sp. n., Xiphinema parasimile, Xiphinema pachtaicum and Xiphinema penevi sp. n. Female: A–D Genital system E–L Vulval region A, E, I Xiphinema browni sp. n. B, F, J Xiphinema parasimile C, D, G, K Xiphinema pachtaicum H, L Xiphinema penevi sp. n. Scale bars: 30 μm (A–H); 12 μm (I–L).