Leucon ( Crymoleucon ) pinocchio, Mühlenhardt-Siegel, 2025

Leucon ( Crymoleucon) pinocchio n.sp.

( Figures 17–19 View FIGURE 17 View FIGURE 18 View FIGURE 19 )

Material:

Holotype ovigerous female, ZMH: K 64953 View Materials , 30 July 2009; SW Atlantic, Brazil Basin, cruise Me 79/1, station # 580, 14° 58.91'S 29° 56.49'W; 5131 m depth; gear: EBS. GoogleMaps

Paratypes:

Argentine Basin:

# 532—EBS: 1 subadult male, 3 non-ovigerous females ( ZMH K 64981 View Materials ) .

# 533—EBS: 1 subadult male (developing pleopods), 1 ovigerous female; 4 non-ovigerous females ( ZMH K 64982 View Materials ) .

# 534—EBS: 6 mancae, 1 ovigerous, 6 non-ovigerous female; 1 VT, broken after carapace; 2 subadult males, 1 adult male (broken after carapace) ( ZMH K 64983 View Materials ) .

Brazil Basin:

#580—EBS: 1 ovigerous females (dissected; ZMH: K 64954 View Materials ).

#558—EBS: 1 non-ovigerous female (ZMH K 64998 View Materials ).

#583—EBS: 2 non-ovigerous females (ZMH K 64984 View Materials ).

#604—EBS: 3 mancae, 4 non-ovigerous females; 2 ovigerous females (ZMH K 64985 View Materials ).

# 605—EBS: 6 non-ovigerous female, 1 ovigerous female, 1 subadult male, 1 young male (pleopods not yet developed), 3 mancae ( ZMH K 64986 View Materials ) .

#609—EBS: 1 manca, 4 non-ovigerous females (ZMH K 64987 View Materials ).

#596—GKG: 1 manca (ZMH K 64988 View Materials ).

Etymology.—The new species with the very long pseudorostrum is named after the famous little boy made of wood whose nose gets very long, described in a children’s book: ”The adventures of Pinocchio” by Carlo Collodi.

Diagnosis.—Pseudorostrum very long, with 0–4 pairs of teeth dorsally and 3–5 pairs of teeth ventrally, length proportions pseudorostrum to rest of carapace is 0.9; carapace with 5 teeth mediodorsally: 3 on frontal lobe, one in the middle and one posteriorly up to almost hind part of carapace; in smaller females only 6 teeth in the anterior part of the carapace; laterally few scattered teeth, 1 tooth laterally on carapace in the region of the frontal suture; antennal notch small to indistinct; ventral margin of carapace serrate.

Description.—Based on holotype, ovigerous female ( Fig. 17 View FIGURE 17 ), 4.6 mm long (ZMH: K 64953 View Materials ).

Carapace with 5 teeth mediodorsally: 3 on frontal lobe, one in the middle and one posteriorly; laterally few scattered teeth, ventral margin serrate; pseudorostrum subacute, very long, 0.9 times as long as rest of carapace, with 5 pairs of teeth dorsally and 8 teeth ventrally; siphonal tube not protruding; ocular lobe reduced; eye lenses missing.

Antennal notch small; 4 small teeth above antennal notch; anterolateral tooth not prominent; integument whitish.

Five free thoracic segments visible.

Pleon little shorter (0.9 times) than carapace and thoracic segments combined; Pleotelson 1.1 times wider than long, anal valves visible from above.

Appendages: ovigerous female ( paratype, ZMH: K 64954 View Materials )

Antenna 1 ( Fig. 18 View FIGURE 18 , A 1 View FIGURE 1 ): relative length of peduncle articles 1 to 3: 28/33/38; 3 plumose setae on article 2, one plumose and one simple setae on article 3; accessory flagellum only little shorter than basal article of main flagellum, with 3 simple setae; main flagellum 4-articulated; the last one tiny, with 2 simple setae; penultimate article with 3 simple setae.

Maxilliped 2 ( Fig. 18 View FIGURE 18 , Mxp2): B/R ratio 0.3, relative length of articles I to D: 10/26/32/21/12; basis with one pappose seta; ischium unarmed; merus with one pappose seta; carpus with 7 setae; propodus with 4 setulate setae (not figured); dactylus with one strong terminal and 5 simple setae sub terminally; rudimentary oostegite with 6 setae.

Maxilliped 3 ( Fig. 18 View FIGURE 18 , Mxp3): B/R ratio 0.9, relative length of articles I to D: 7/21/25/27/20; basis with 4 pappose setae, 3 strong pappose setae on outer distal corner; ischium unarmed; merus with 2 pappose setae along inner margin, one strong pappose seta on outer distal edge; carpus with 4 pappose setae; propodus with one simple seta on outer distal corner; dactylus with 5 simple setae distally; exopod present, with 2 teeth on basal article.

Pereiopod 1 ( Fig. 18 View FIGURE 18 , P 1 View FIGURE 1 ): B/R ratio 0.6, relative length of articles I to D: 8/13/29/32/18; basis with 5 teeth along margin, with 5 pappose setae; ischium unarmed; merus with one pappose seta; carpus with 6 pappose setae; propodus with 4 simple setae; dactylus with 2 simple setae along margins, 5 simple setae terminally and sub terminally; exopod present, with 2 teeth on basal article.

Pereiopod 2 ( Fig. 19 View FIGURE 19 , P 2 View FIGURE 2 ): B/R ratio 0.9, relative length of articles I to D: 3/18/30/15/33; basis with 6 pappose setae along margin; ischium unarmed; merus with one pappose seta; carpus with 5 pappose setae and 3 simple setae; propodus unarmed; dactylus with 4 pappose and 4 simple setae; exopod present, basal article with 2 teeth.

Pereiopod 3 ( Fig. 19 View FIGURE 19 , P 3 View FIGURE 3 ): B/R ratio 1.7, relative length of articles I to D: 16/21/33/21/9; basis with 4 pappose setae; ischium with one pappose seta; merus with one pappose seta; carpus with 2 simple setae; propodus with one simple seta; dactylus with one strong simple seta terminally; exopod present, with one tooth on basal article.

Pereiopod 4 ( Fig. 19 View FIGURE 19 , P 4 View FIGURE 4 ): B/R ratio 1.4, relative length of articles I to D: 11/26/33/22/9; basis with 4 pappose setae; ischium with one pappose seta; merus with one pappose seta; carpus with one pappose seta; propodus with one pappose seta; dactylus with one strong terminal seta (broken).

Pereiopod 5 ( Fig. 19 View FIGURE 19 , P 5 View FIGURE 5 ): B/R ratio 1.1, relative length of articles I to D: 16/25/30/19/11; basis with 4 pappose setae; ischium with one pappose seta; merus unarmed; carpus with 2 pappose setae; propodus unarmed; dactylus with one strong terminal and one thin subterminal seta.

Uropods ( Fig. 19 View FIGURE 19 , U), pleotelson 0.7 times of uropod peduncle, peduncle with 3 setae along inner margin, little (0.9 times) shorter than uropod endopod basal article; exopod shorter than endopod; endopod 2 articulated; basal article with 6 setae along inner margin, 2.3 times longer than distal article; distal article with one seta on inner margin, 3 strong setae terminally.

Distribution: Argentine and Brazil Basin, 4602–4608 m depth.

Remarks: There are 7 species with a very long pseudorostrum described for the subgenus Leucon ( Crymoleucon) : L. longirhinus Mühlenhardt-Siegel, 2011 (Southern Oceans, 1983–4676), L. grandidentatus Mühlenhardt-Siegel 2011 (Southern Oceans, 3784–4698 m), L. macrorhinus Fage, 1951 (Mediterranean, 200–1529 m), L. savulescui Petrescu, 1992 ( Peru Trench, 4661–4723 m), L. serrulirostris Ledoyer, 1988 (eastern Africa, 3716 m), L. nudirhinus Mühlenhardt-Siegel , 205 ( Angola Basin, 5395–5415 m), and L. tener Hansen, 1920 (Arctic waters, NE Atlantic, 698–2702 m). The new species resembles L. longirhinus and L. savulescui in possessing teeth above the subrostral notch. Both species have 2 or 3 teeth above the subrostral notch while the new species has 4 teeth. The other 5 species have no teeth above the subrostral notch. The new species differs from both L. longirhinus and L. savulescui in the presence of teeth on the dorsal side of the pseudorostrum, which are lacking in both L. longirhinus and L. savulescui .

The dorsomedian serration on the carapace reaches almost to the hind margin of the carapace, is doubled and more separated in the posterior part in L. savulescui , while in L. longirhinus the dorsomedian serration consists of 10 teeth and reaches up to 2/3 of the carapace; in the new species the dorsomedian serration has only 5 teeth, 3 on the anterior part of the frontal lobe, one in the middle and one close to the posterior margin of the carapace.

In the new species the pseudorostrum is quite acute, whereas it is blunt in L. longirhinus and with 2 small teeth on the tip in L. savulescui . Also the length proportion of the pseudorostrum to rest of carapace is different in the 3 species: 0.9 in the new species, but 0.4 in L. savulescui and L. longirhinus .